The basic premise of the Rolfing® Structural Integration process is to address the body’s alignment
and integration in gravity. The Rolfing Ten Series® brings the client closer to their core line, their vertical center, allowing them to move harmoniously and naturally with the pull of gravity throughout their body as they move. Being balanced offers more economic movements and improved overall well- being. Since French Rolfer® Hubert Godard’s insights into tonic function for exploring movement, Rolfers® are very aware of the continuous sensorimotor feedback our body experiences while in the field of gravity (Newton 1992, Frank 1995). Motor output generates sensory information, and sensory information initiates/modulates motor action. Our internal (body) and external (context) environments are in constant communication, a feedback loop. And gravity is constant.
As a sports scientist, athlete, and Rolfer, I am passionate about the force and power generating capacities of human locomotion. Rolfing Structural Integration’s unique perspective and conceptualization of movement made me realize how these raw physical capacities are integrated within a sensory- coordinative framework, embedded in the gravitational field. After some years of trying out and probing for myself, I came to the conclusion that our Rolfing world and the weight room are not that far apart as I initially presumed. We often think of fascia, muscle, and nervous system tissue as behaving in a relaxed, conscious mode of movement; the moment we engage in an explosive, high-impact activity, the sensory-motor context changes completely, calling for a very different set of structural and psychobiological responses. Moreover, exercise interventions don’t need to be flashy or overly complicated to address a client’s needs. In my practice, I try to embrace my clients’ movement habits and their distinct physical qualities, assessing the clients’ force-production capacities if needed. It is exciting to see how at the right time during the Rolfing process, the introduction of appropriate strength exercises can foster our structural work on the table.
The moment we engage in movement, in addition to our present sensorimotor state, internal and external forces with their own distinct sensorimotor qualities will act upon our bodies. The intensity and velocity of these forces, as well as our emotional state and the context of our surroundings – the movement context – all have an impact on our body’s processing and response to a motor demand. The chaotic nature of our environment requires the human body to be adaptable and cope with various degrees of forces continuously acting upon it. Gravity meets movement. In this article, I present to you a condensed version of the ideas originally written in a paper for my application to be an anatomy instructor for the European Rolfing® Association e.V., and I have made some amendments to this version for a broader audience. My goal is to integrate insights from sports science, biomechanics, and neurology to explore force and power production and its relevance to Rolfing Structural Integration.
Newtonian mechanics describes force as a faculty that can change an object’s velocity (force = mass x acceleration). Force has directionality, and its vector is represented by a line with an arrow indicating the direction of force. In kinetics, the branch of science that deals with the effects of forces on bodies, this is further specified by distinguishing between internal and external forces. Hence, a movement can be either initiated, arrested, or modified from within our body’s anatomy (actively via muscle or passively via connective tissue) or from entities meeting our structure from the outside (e.g., gravity). The term strength is defined more practically as the human exertion of force on a physical object (Neumann 2017).
Power, on the other hand, expresses the relationship between force and speed (power = force x velocity). Its focal point is
the body’s ability to generate the greatest amount of force in the quickest way possible, which can be further elaborated as the transfer of energy per time. Kinetic energy, the form of energy that allows a mass to have motion, in its simplest understanding, is directly proportional to the object’s mass and the square of its velocity. In contrast to force, power is a scalar quantity, meaning it measures the rate of energy transfer and not direction (it is not a vectorial quantity), although its assertions are only valid when force and velocity are oriented in the same direction.
Force and power have an inverse relationship within the context of a constant power output. Quite practically, a high-power output can only occur at compromised levels of either force or contraction speed. The faster a movement becomes, the less absolute force can be produced, and vice versa. This is a feature to keep in mind when biomechanical theory about the human body is transferred into the field practice of athletic performance and physically demanding occupations. But, it is important to note that the literature on strength, power, and speed is clear about maximum strength being the basic property involved in the highest possible power output (Wang et al. 2023). This is predicated on the specific neuromuscular and myofascial adaptation process of strength exercise.
The structural makeup of different muscles, muscle groups, and their connective tissue content influences the ability of the human body to produce force and power in a distinct manner. Muscles and the fibers that they’re made of are encased in layers of connective tissue – the epimysium, the perimysium, and the endomysium1. These tissue layers are the myofascial component, known as myofascia, organized in a coherent fashion throughout the body with the neurofascia, viscerofascia, and superficial fascia, in totality called the human fascial system (Stecco et al. 2025). Fiber numbers in muscles can range from a few hundred to over a million. The smallest contractile unit of a muscle is the sarcomere, and it is stacked in a way that gives the musculature of the locomotive system its striated appearance (Schoenfeld 2021).
A muscle’s fascial layers directly participate in the transmission, stabilization, modulation, and amplification of muscular strength as the sarcomeres contract. Not only does the fascia transmit the force resulting from a muscular contraction longitudinally via the muscle’s tendons, but it also transmits laterally between neighboring fibers and even neighboring muscles (up to 30% of force transmission is intermuscular). The effectiveness of a muscular contraction depends on the state of the fascia, the collagenous matrix in which the muscles are invested. Fascial tension amplifies muscular strength, comparable with a hydraulic pressure system: as a muscle contracts, it widens and hence, increases the intra-fascial pressure, resulting in an amplification of the muscular force produced (Pilat 2022).
In order to estimate a muscle’s contractile strength, physiologists determine the physiological cross-sectional area (PCSA), which is the peak area of a muscle’s cross-section perpendicular to its fiber orientation. Generally, the larger the PCSA, the higher the potential muscle force output. An increase in PCSA (i.e., hypertrophy) can be defined as the parallel/ serial addition of sarcomeres, an increase in the amount of connective tissue, and an enhanced sarcoplasmic fluid content. Parallel adding is mostly achieved through concentric workloads; in-series adding can be observed in cases where muscles must adapt to a new functional length (e.g., loaded stretching, like eccentric-focused training). Sarcomere adding and arrangement are more or less genetically determined. Whereas a parallel sarcomere arrangement allows greater force production and strength, a serial sarcomere arrangement is associated with greater speed of contraction (Schoenfeld 2021).
In conjunction with the PCSA, a muscle’s innate architecture further dictates its contractile properties. Fiber length and fiber angulation influence the relative PCSA and hence contribute to the force and speed of contraction. In general, thick and short muscles (e.g., m. gluteus maximus) are able to produce higher forces, whereas long muscles (e.g., m. rectus femoris) show a high contraction velocity. The reason is the sarcomere arrangement. In muscles showing a pennate fiber organization, that is to say, the fibers are oriented at an angle to the line of action, leads to an increased PSCA. Consequently, a pennate fiber arrangement allows muscle, relative to its length and mass, to contract more forcefully, even over a larger distance.
As fiber angulation increases, so does the PCSA, and hence, increasing the force- producing capacities, while at the same rate, contraction velocity decreases. A classic example would be m. fibularis longus. The majority of muscles in the human body show a parallel fiber arrangement, their fibers are oriented in direction with the line of action. The linear organization allows the fibers to contract fast and extensively, but following the laws of mechanics, with relatively less force. Fusiform, strap, and convergent muscles display a parallel fiber organization (Bosch 2015, Wackwitz et al. 2024).
In summary, the structural makeup of the fascial tissue of a muscle will amplify that muscle’s force production capacities. The fascial tissue amplifies a muscle’s strength. Due to the triple- helical organization of the collagen fibers of the fascia and the unique orientation of the fibers they constitute, collagen fibers actively participate in the storage, transmission, and release of kinetic energy. Some muscles have higher connective tissue content, but not all of them. That’s why different muscles have different mechanical properties. The muscular tissue is embedded within a denser and more comprehensive collagenous matrix. Similar to the relatively larger PCSA of some muscles due to the angulation of their fibers, an increase in a muscle’s connective tissue content will also contribute to an enlarged PCSA. Keep in mind that while some muscles appear long and thin (like m. rectus abdominis or m. ischiocrurales), they have a relatively large PCSA due to the high proportion of connective tissue associated with the muscle fibers. This means they are capable of producing a relatively high force. Their high connective tissue content, combined with their large PCSA, makes those muscles prone to high-impact, powerful movements.
The Hill model explains how elastic properties are utilized in a movement context (Pilat 2022; Bosch 2015). This introduces a physical reality into our thinking about force and power, as well as its physiological implications. How the morphological make-up of muscular tissue is more or less prone to certain types of effort, and how fascia (the tissue of our focus) has its rightful place within the context of force and power.
The Hill model distinguishes between contractile elements (i.e., muscle fibers), elastic elements that are together in series (i.e., tendons and investing fascia), and parallel elastic components (i.e., passive connective tissue) in a muscle. In the case where an opposing torque exceeds a muscle’s contractile elements’ isometric capacity, the muscle will lengthen and the series elastic elements will stretch. If the contractile element can isometrically match the opposing torque, that is to say, the forces would be equal
The Hill model.
in measure, the series elastic parts are now in a position to store and release elastic energy. And remember, isometric strength, such as when gripping a weight and holding it steady, by definition, involves no movement but does have a high level of tension in the muscle. In order for a muscle to make use of the particular mechanical properties of the fascia, that muscle’s fibers must bear the potential to produce peak isometric forces. Only then can proper storage, transmission, and release of kinetic energy happen.
The hamstring group is a prime example. When running, sprinters experience ground reaction forces of three to six times their body weight. In order to counteract and adapt to this impact, the hamstrings must be able to produce peak isometric forces themselves (Bosch 2015, Rochau et al. 2024).
Our colleague, fellow Rolfer, Robert Schleip, PhD, describes a similar phenomenon in the paper, “Training Principles for Fascia Connective Tissues” (Schleip and Müller 2013). Schleip and Müller (2013) describe how various forms of tissue strain influence the fascia. Actively loaded stretches appear to stimulate the fascial web in the most comprehensive way, the different strands of collagen (serial, extra-muscular-transverse, parallel) are addressed almost entirely. For this to happen, the muscle needs to be contracted isometrically. Among other things, Schleip and Müller recommend that athletes incorporate counter-movements and pre-stretches into their training routine to make use of the mechanical properties of fascia and address the fascial sheet comprehensively. In the context of high-impact movements, I would disagree with these recommendations. I will elaborate further in a moment.
The central nervous system of humans is able to recruit 75% of muscle fibers for voluntary concentric action (i.e., maximum voluntary contraction). In other words, our brain underestimates the body’s muscular capacities in order to protect its structural integrity (i.e., autonomously protected reserve). If humans were able to voluntarily contract all of their muscle fibers at the same time, maximally, the force generated would be strong enough to rip the flesh from the bone.
Force production happens due to the size of the stimulus experienced. Following the so-called size principle, low-threshold motor units (slow-twitch fibers) get activated first, whereas high-threshold motor units (fast-twitch fibers) need a stronger stimulus to get recruited. Under a sub-maximal load, the human body can produce a maximal counter-force only when recruiting low- and high-threshold motor units alike, synchronizing slow-twitch-fiber and fast-twitch-fiber activation.
The size principle makes it possible for the central nervous system to estimate force production more efficiently. It is important to note that the regulation of (high) force and power production mostly takes place at the spinal cord level by way
of reflex arcs. The higher-order central nervous system regions (basal ganglia, cerebellum, motor cortex) then modulate what can be regulated automatically at the spinal level.
Athletes and people with physically demanding jobs must be able to execute fast movements, often with a lot of strength. The high-impact movements will at times be responses through the reflex arc mechanism. This mechanism makes a lot of sense since supraspinal/cortical processing of high-impact sensorimotor information takes longer to neurologically process, and the need to react quickly would take a cortical response too much time. Depending on where you focus in the literature, monosynaptic reflexes have a latency of twenty to forty milliseconds, whereas the reaction time for voluntary movements (which includes sensory input
+ brain processing + muscle action) takes between 200 to 250 milliseconds. Yet, signaling through the spinal pathway is still not fast enough when our body needs to react, generate, or modulate peak forces. A more rapid control is needed. The key component of this demand is the mechanical properties of myofascial and the human body’s coordinative ability to control high-impact sensorimotor feedback (Eisen et al. 1985, Bosch 2015, Kim et al. 2022).
The Rolfing Ten Series emphasizes the importance of the gamma motor system due to its key role in our constant engagement with gravity. When it comes to force and power production, the gamma system must be able to adapt to the changing sensorimotor context of high-impact movement. Gamma-system regulation is predominantly achieved through the proprioceptive organs of the alpha fibers and the muscle spindles, in accordance with the Golgi tendon organs.2 Muscle spindles are intrafusal structures that are three to seven millimeters long. They are sensory receptors located in the perimysial and endomysial fascia, parallel to extrafusal muscle fibers, and they transmit changes in the muscle fiber length to the central nervous system.3 They communicate to the central nervous system about the change in length within itself and the speed of that change of length. This information is processed by alpha and gamma motor neurons alike. The alpha motor neurons activate associated extrafusal muscle fibers (i.e., stretch reflex), whereas the gamma motor neurons stimulate intrafusal muscle fibers. This alpha-gamma coactivation enables our body to continuously maintain and fine-tune a particular fiber length, even under the influence of perturbing external and/or internal forces.
The Golgi tendon organs are sensory receptors located at the border between muscle and tendon (i.e., the myotendinous junction), which monitor a muscle’s force output. By being stretched passively, one Golgi tendon organ registers the tensing of the fibers of one motor unit (i.e., ten to twenty muscle fibers per Golgi tendon organ). Depending on stimulus size, the agonist motor unit (the motor neuron and its muscle fibers driving the voluntary movement) will be inhibited by spinal interneurons, while the antagonist motor neurons will be stimulated (the motor neuron and muscle fibers that oppose the voluntary movement) through the Golgi tendon reflex. The Golgi tendon organ pathway continuously provides our body with precise information about muscle force, thus allowing us to maintain steady levels of muscular tension to counteract perturbing forces (Juhan 2003).
The permanent excitatory and inhibitory interplay between muscle spindle and Golgi tendon organ activity sets the tone for movement patterns to be executed efficiently, while constantly readjusting to unpredictable external and/ or internal forces. More strenuous and intense activities will produce a different sensorimotor context, an environment that muscle spindles and Golgi tendon organs will experience and process differently. Besides the predominant structures and pathways of pure motor control, it is important to note that complex cortical networks modulate movement initiation and execution via sympathetic pathways to the adrenal medulla and vice versa. Thus, the affective state we’re in will greatly influence our capacity to execute movements (Dum, Levinthal, and Strick 2019).
The discussion about isometric loading, high-impact movement, reflex arcs, and the interplay between muscle spindle and Golgi tendon organ activity is compelling; they are neuromuscular and biomechanical peculiarities about force and power production, and may have already provided an incentive to rethink some of the approaches we Rolfers use in our daily manual and movement practice. Our nervous system reacts and adapts to the sensorimotor context in which we find ourselves. Furthermore, the diversity of muscle architecture can provide us with new practical implications on how to approach these structures manually or with movement. Loading each myofascial structure in the same way, or just releasing tissue tension throughout the whole body, would negate the innate peculiarities of different myofascial and neuromuscular structures in the context of high-intensity movement.
Under the influence of high forces, the need to adapt to a more strenuous environment will create an equivalent sensorimotor context. For example, a Rugby player experiences constant changes in force and speed during a match. The consequential sensorimotor chaos has to be controlled in order for the athlete to perform the necessary motor response that is forceful, fast, and also economical. In my understanding, the tools we Rolfers offer to such an athlete may be limited and even insufficient to assist our exemplary Rugby player in dealing with the demands of the sport. But, becoming aware of the influence of high forces will not only help you with your work with athletes, but also with laborers, tradespeople, farmers, and blue-collar workers alike to adapt to and generate high forces in their daily work.
Strength, the exertion of force on an object, is highly situation-dependent. The demands of the environment change constantly, hence the sensorimotor tasks involved are highly variable. Therefore, the ability to maximally contract a muscle must be rooted in a coordinative framework of movement. Nikolai Aleksandrovich Bernstein (1896- 1966) was a Soviet neurophysiologist and biomechanist responsible for introducing the hierarchies of movement construction (Profeta and Turvey 2018, Derouesné 2022), and his probability theory can be a useful tool to address this process. According to Bernstein’s probability theory, the central nervous system estimates its environment and anticipates a desired future state plus the necessary properties available to achieve that. It is an estimation of the sensory and motor signals arising after the desired movement. Therefore, the central nervous system relies on past experiences and a fixed set of previous successful motor actions. The estimated state and consequential force production – the future sensorimotor context – after a yoga asana, chopping firewood, catching a football, or tackling an opponent, to give you several examples, will be completely different from each other. But, to be able to rely on a fixed set of successful motor answers, our body has to find out which movements are the most effective and economical.
Since movement most often includes several joints, each with its own particular range of motion (ROM), our body is faced with numerous possible ROM combinations to produce the desired movement. But a body confronted with peak forces must be able to initiate an appropriate motor response quickly. For this reason, our central nervous system eliminates superfluous alternatives in joint articulation to produce the most effective and economical motor response. In light of this challenge, I would disagree with the conviction of many of my Rolfing colleagues that we should categorically aim for increasing ROM in our clients. An enhanced range of joint articulation does not transfer automatically into a more powerful motor response. Again, the sensorimotor context is different.
ombinations to produce the desired movement. But a body confronted with peak forces must be able to initiate an appropriate motor response quickly. For this reason, our central nervous system eliminates superfluous alternatives in joint articulation to produce the most effective and economical motor response. In light of this challenge, I would disagree with the conviction of many of my Rolfing colleagues that we should categorically aim for increasing ROM in our clients. An enhanced range of joint articulation does not transfer automatically into a more powerful motor response. Again, the sensorimotor context is different. In my professional practice as a strength and conditioning coach, I often encounter this issue with dedicated yogis who wish to participate in power- and force-
oriented sports. Despite their great range of motion, they often lack the ability to react fast and/or powerfully. In this regard, Alfonso et al. (2021) argue that strength training can be as effective as stretching in increasing ROM. I will elaborate further on the topic of ROM when talking about biarticular muscles. To address the force and power-producing capacities of our body, we need to be aware of the musculoskeletal structures that are more prone to coping with high-
impact perturbations. Additionally, motor patterns that provide the most robust answer to the movement must be found. These motor patterns should be stable and economical, yet flexible enough to react to environmental changes.
C) Reflex-Supported Approaches
One way to approach the task at hand lies within our central nervous system, specifically in the primary rhythmic patterns of movement or reflexes. These are automatic stereotypical motor reactions in response to particular stimuli. The consequential intermuscular movement patterns are constantly adjusted and readjusted due to the permanent flow of sensory information. A reflex-supported approach allows our body to respond with a basic set of motor responses to the demands of a changing environment. Two such primary reflexes are the ‘stumble reflex’ and the ‘crossed extensor reflex’. The stumble reflex states that moving one leg posterior (e.g., the stance leg in relation to the trunk) will cause the other leg to move anterior (i.e., the swing leg). The crossed extensor reflex, on the other hand, states that flexion of the swing leg (triple-flexion of hip, knee, and ankle) is linked to extension of the stance leg (triple-extension of hip, knee, and ankle), plus elevation of the pelvis on the swing side. The rapid succession of excitation and inhibition in high-impact movements needs reflex support in order to meet the peak external perturbations fast yet purposefully.
D) Co-Contractions
The faster and more powerful a movement becomes, the more signaling errors the central nervous system will produce. The need to stabilize motor signaling can be ensured by the simultaneous action of agonists and antagonists. Co- contractions around joints, particularly relevant for certain movement patterns, regulate pretension and hence protect the joint. The consequential joint stiffness limits muscle slack and excessive pre- stretching, both of which have been identified to compromise speed and power (Bosch 2015). Balanced co-contractions depend on the innate architecture of the myofascial and its elastic properties. Hence, some structures are more suited to remain in a co-contracted state during movement. In running and sprinting, the hip would be a prime example where co- contraction is advisable. At toe-off, the knee and hip extend in the sagittal plane. This extension is necessary to transmit elastic energy. A more economical and faster transfer of energy happens only when the hip stays in a locked position at the end of the extension. Otherwise, excessive movements in and around the pelvis must be compensated; transfer of energy is compromised.
E) Dynamic Systems Theory – Attractors and Fluctuators
Another way of establishing robust motor patterns can be achieved by implementing the concept of ‘attractors’ and ‘fluctuators’ from dynamic systems theory (Bosch 2015). In biomechanical terms, attractors are defined as stable and economical motor patterns deriving from the inherent biomechanical logic of our musculoskeletal system. They are abstract motor principles, close to the aforementioned reflex patterns. Under
the influence of rapid and high-impact environmental changes, attractors can provide our body with more controllable motor responses. Fluctuators, on the other hand, are less stable, high-energy cost motor patterns. But, contrary to attractors, they are very adaptable to change. Both attractors and fluctuators feed into the self-organization potential of our body in a constantly changing environment. As a strength and conditioning coach and manual therapist, I focus on identifying both persistent and transient movement patterns within the client at hand.
F) Biarticular Muscles and Co- Contractions as Attractors
Biarticular muscles, those that relate to two joints, due to the nature of their spatial organization, rarely change their total length during movement (i.e., they have a constant ROM). Hamstring action during running is a good example of this phenomenon. Their predominant job is the transfer of kinetic energy. As I mentioned above, the transfer of energy happens best when a muscle is contracted isometrically. Sports scientists and biomechanical researchers have reported on the responsiveness of the mechanical properties of fascia being almost nil (Bosch 2015). This phenomenon is called ‘preflexes’. The more strenuous and faster a movement becomes, the higher the need to control the subsequent sensorimotor chaos. Extrafusal alpha signaling travels at around fifty to sixty millimeters per second, and intrafusal gamma signaling ranges from four to twenty-four millimeters per second. Compared to preflex responsiveness, alpha- and gamma-signaling takes too much time.
Applying the idea of attractors and fluctuators, the hamstrings should then be trained to remain in an attractor state during sprinting. Meaning, they must be trained to generate peak isometric forces at a particular length in order for the connective tissue to function in a preflex manner. As described above, this derives from their particular structural organization and myofascial makeup. As coaches and manual therapists, we can facilitate this process by prescribing submaximal isometric strength training in addition to their manual protocol.
Peak isometric strength is strongly associated with enhanced fiber recruitment and power output. In contrast to a 75%
maximum voluntary contraction, some sport scientists claim that the human body is capable of contracting 85% of its muscle fibers in an isometric manner (Schoenfeld 2021). Considering the aforementioned high ground-reaction forces a sprinter has to cope with, about three to six times their body weight, our body should be able to create a counter- force high enough to withstand this impact. Co-contractions around the hip would be another example of a function to preferably be in an attractor state during high-impact movements. Single- leg hinge exercises with a moderate load, performed explosively, can help establish sufficient co-contractions around the hip. The goal is to stabilize the hip in extension at the end of the movement. In this way, the body is taught to generate peak forces around a joint in an end-range position quickly. I have elaborated on the advantages of co- contractions, which effectively stabilize a joint via agonist-antagonist contraction, preventing excessive movements from being compensated for. This allows the elastic properties of the myofascial system to transmit and release kinetic energy effectively.
The peculiarities of biarticular muscles and the coordinative challenges during high-impact movements, as I have already mentioned, lead me to disagree with Dr. Schleip’s recommendation to explicitly integrate counter-movements and pre- stretches into an athlete’s workout routine in order to make use of fascia’s mechanical peculiarities. Especially for power athletes, high-impact environments call for peak force and power responses. Pre-stretches and counter-movements further stretch the tissue. Muscles that work best at a particular length – like the group of biarticular muscles or muscles with a high connective tissue content – are now brought into a position where an additional distance has to be covered. This will require additional force and time. The Hill model clearly demonstrated that by means of counter-movements, muscle slack increases and the capacity to store elastic energy is reduced. Counter- movements and pre-stretches can affect human explosive power in the initial phase of training this specific capacity, and can be a safe method for beginners. But due to the low-level loading, these two methods appear disadvantageous compared to loaded high-impact exercises in the long term.
As Rolfers , I would suggest that we rethink some of our propositions on particular myofascial structures and update our concepts about movement.
One of the main anatomical structures addressed in the first session of the Rolfing Ten Series , known as the First Hour, is the hamstring group. In order
to foster better breathing, we are taught to release tension from the posterior thigh. In theory, this allows the pelvis to be more aligned with the thorax and hence the diaphragmatic movement in breathing. But what does ‘releasing tension’ mean, and what will that do in terms of hamstring function? In my understanding, tight hamstrings are rarely the prime lesion. Among numerous other possibilities, hamstring tightness is most often a compensatory tension due to physical inactivity or secondary to hip flexor tightness (m. rectus femoris or iliacus in particular).
Releasing the fascial tension in the hamstring compartment may result in a sense of well-being and maybe in a repositioning of the pelvis. However, it does not guarantee an improvement in hamstring function during high-impact movement. The sensorimotor context (e.g., torque, joint angle, and velocity) will be completely different. To withstand and meet external perturbations effectively, they must be trained to generate peak isometric forces (Rochau et al. 2024). Releasing tension and teaching a power athlete the ‘pelvic rock’ afterwards will not transfer into enhanced movement execution.
A) Neuromuscular Testing for Hip
Extensors
Among manual therapists, Rolfers bear the unique potential to relate our clients’ structure to their sensorimotor context. We are aware of what sport scientists call ‘transferability’, which is the similarity in intermuscular coordination between exercise and performance. By addressing the structure meaningfully with our hands, we can establish a relationship within the tissue.
Apart from our traditional approaches, I would suggest incorporating neuromuscular testing with power athletes, specifically examining the firing pattern of their hip extensors (i.e., the gluteus maximus and hamstrings). This can be done with the athlete in the prone
position. To test hamstring availability, the client flexes one knee to one hundred degrees and attempts to resist the subsequent pull from the practitioner to extend the knee. The client should be able to sufficiently withstand forced knee extension. Look closely to spot any compensatory patterns arising from the client’s effort. Flexion of the ipsilateral hip plus spinal flexion is a typical compensatory pattern. For further refinement, the leg to be tested can be rotated internally and externally to emphasize either semimembranosus, semitendinosus, or biceps femoris activity. I would recommend including the gluteus maximus in this testing scheme. The m. gluteus maximus sets the stage for the hamstrings to transfer kinetic energy. During the stance phase of running, the gluteus maximus helps stabilize the trunk in an upright position by extending the hip of the stance leg. The hamstrings are now in a position to transfer energy and don’t have to compensate for a lack of hip or trunk stability. This is important to remember when interpreting the results of the gluteus maximus test.
To do the gluteus maximus test, the client is in the prone position. One leg is flexed to ninety degrees at the knee, and the knee is slightly elevated above the table, allowing for hip extension. Place one hand on the contralateral ilium, holding the client on the table, and the other hand on the ipsilateral hamstring. The client is instructed to resist the therapist’s push to extend the knee. A sufficient gluteus maximus firing pattern would enable the practitioner to put almost all their weight on the elevated leg. Typical compensatory patterns are spinal hyperextension and rotation. Accessory movements can give us hints on additional areas of the body to work on manually.
Bernstein’s probability theory and the action effect hypothesis can facilitate the process of motor learning and exercise design. The action-effect hypothesis states that movements are best planned and controlled based on intention and the outcome of the movement, rather than by focusing on the movements themselves. Motor learning is improved when an athlete provides sensory feedback about their sensorimotor state after a movement. Only the most effective motor control mechanisms, which are motor patterns proven to be stable enough under the influence of a rapidly changing environment, will be stored by our central nervous system, which is yet another circumscription for attractor.
Two things are important when applying this concept. First, movements must be executed with maximal intent. Gonzáles- Badillo et al. (2014) found that participants who intentionally lifted a bar quickly had significantly greater strength gains than the control group, which lifted at normal speed. Through further refinement in training, the initial sensorimotor chaos will eventually become more controllable. Secondly, top performance needs fluctuator flexibility. Although attractors are easy to practice, they bear the risk of becoming rigid and monotonous.
The sensorimotor context of high- impact movements is a constant state of excitatory and inhibitory chaos. We need variability in our movement practice to react to this chaos with a certain degree of spontaneity. One method of achieving this would be to ‘detach’ an attractor pattern from its context and perform it under unstable conditions. Practically, a triple extension of the stance leg and the subsequent hip lock can be performed on an unstable platform or with a water bag swung overhead. Rolfing Structural Integration’s unique approach to the hapticity of the feet and their interdependence with the hip and spine can serve as a distinct resource to foster better stability under the influence of external perturbations.
Now that I have explained the structural peculiarities of myofascia in view of force and power production, as Rolfers, I think we should educate ourselves on some of these anatomical peculiarities, especially when working with athletes or people
whose work requires them to use their strength and power. Some structures are more prone to force production, while others have higher contraction velocities. The abdominal and erector spinae muscles both show a pennate fiber orientation and relatively high amounts of intramuscular connective tissue. Accordingly, they show great maximal force production capacities at a particular fiber length. In terms of running, the abdominal and erector spinae muscles should be adapted to stabilize the trunk and prevent excessive rotation. This guarantees a more economical transfer of kinetic energy from the lower to the upper body.
As mentioned above, the intra-fascial pressure created through muscular contraction can further amplify the force produced. It is within the thoracolumbar fascia, where these two structures meet, that dynamic stability is created, allowing for the proper transfer of kinetic energy. Our traditional Rolfing approach works with the deep fascia of the back, and its various interdependencies can be further complemented by taking this biomechanical peculiarity into account. The Rolfers’ beloved psoas plays a key part in loading the hamstrings of the swing leg during running. First, the abdominals and erector spinae must be sufficient to control excessive trunk rotations. The psoas of the stance leg is now in a position to integrate the sensorial information coming from hip extension and to prevent excessive extension of the hip. Furthermore, the psoas’ isometric pretension allows for a subsequent powerful flexion of the hip. Hip flexion should occur as rapidly as possible and to a minimum of ninety degrees. The swing leg is now brought into a position where foot-plant and loading of the hamstrings can happen in the direction of the ground reaction force.
A psoas that has to compensate for a lack of trunk stability will not be in a position to sufficiently integrate sensorial information and contract powerfully. ‘Freeing’ the psoas manually, as we do in the Fifth Hour of the Rolfing Ten Series, and educating the client to access their psoas in walking can be regarded as part of a more comprehensive protocol. Further education could be offered where the person’s psoas could be trained within the coordinative context of explosive and forceful movements. The aforementioned intermuscular interdependencies and the psoas’ role in a particular sensorimotor environment are considerations to keep in mind when creating exercises or teaching movement.
D) Changing Perception on Manual Input
Scientists have clarified what happens to myofascial tissue when a mechanical stressor in the form of a manual therapeutic intervention is applied to the human body. The stressor can be pressure or shearing tension. Depending on the intensity of the initial forces, the vector of that force, and the kinetic state of the various components of the connective tissue matrix, each individual will respond differently.
When receiving a tensional load, the fibroblasts (cells that produce collagen fibers within the myofascial layers) reorient in the direction of the greatest mechanical stress. As the conditions within the tissue change, fibroblasts start to remodel the extracellular matrix, also known as the interstitium (Benias et al. 2018). In the presence of different growth factors, collagen synthesis is upregulated, as well as the extracellular matrix’s water-binding capacities. As the intensity of manual pressure and shear tension increases, so does the expression of proinflammatory cytokines (a group of proteins involved in local cellular communication, which are part of the immune system’s response). The cytokines expressed by the fibroblasts can also decrease collagen synthesis and upregulate deposition of superfluous collagen fibers. The mechanical input is translated into a chemical reaction (a mechanism called mechanotransduction). This is the process of fascial remodeling, and it requires both mechanisms to function properly and in synchrony. It enables our fascia to maintain its high degree of dynamic and contextual stability (Schleip et al. 2012, Pilat 2022). Under pressure and compression, myofascial tissue exhibits a distinct behavior. The force and power imposed on the tissue initiates and sustains tensotaxis, a phenomenon where tensile stress or strain affects cell migration (Lin et al. 2009). As the tensotaxis within the tissue changes, the afferent signaling from the various intrafascial receptors and nerve endings decreases. This change in mechanosensitive information will be processed by the central and autonomic nervous systems, often resulting in a subsequent release of tension due to parasympathetic signaling (Chaitow 1996). The moment we Rolfers apply an intentional force, with a specific amount of power, to the fascia of our client, we foster remodeling and reorganization. Since our nervous system receives most of the information on the tensional state of our body’s tissues from receptors and nerve endings in the connective tissue, a properly functioning fascia system is indispensable for any meaningful and coordinated motor action. But the mechanical stressor leading to a change in fascia tissue organization can also come from repeated high-impact movements. The difference between the input we deliver as Rolfers and the perturbatory forces of a high-impact movement lies in the magnitude of force and the sensorimotor context. It is our responsibility as manual therapists to recognize the distinct features of our clients’ movement context and develop strategies to support maintenance, development, and/or strengthening on the table through purposeful manual intervention. In light of all this information about strength and power, the targeted muscle groups, their anatomical and biomechanical peculiarities, and their distinct place in the movement context of our client must be evaluated thoughtfully. Using the hip extensor muscles as an example again, before balancing the fascial tension within these structures, test how they behave under a more strenuous load using the neuromuscular testing protocol. Evaluate how your client is able to integrate these specific movement contexts and how a manual and/or exercise intervention could benefit them.
Perception of Strength and Power within the Rolfing Community
In my view, our Rolfing community should reconsider some of the prejudices surrounding strength training. The literature on the long-term benefits for human health is becoming more robust. Apart from our association of muscles and strength as merely mechanical properties, the human musculature must also be considered as an organ of metabolic health. Higher lean muscle mass in the elderly is associated with a significantly reduced risk of diabetes, Alzheimer’s disease, stroke, heart attack, and other metabolic dysfunctions. Sarcopenia, the age-related loss of muscle mass and motor competence in our society, is nothing short of an epidemic. In a study by Lauersen, Bertelsen, and Andersen (2014), it was found that stretching decreases injury risk by 4%, whereas strength training decreases injury risk by 69%. Frequenting the weight room more often can not only slow down sarcopenia, but also help us maintain our capacity for meaningful movement. Sometimes our environment requires that our movement be more strenuous and faster.
Releasing tissue and educating our clients to move more harmoniously is a unique feature of our work, but the human structure behaves differently when faced with peak external forces and the resulting need to react quickly. This applies to both athletes and laborers. As Rolfers, we should be more aware of the particular needs of those populations and the benefits our work can bring to them. Rolfing Structural Integration’s unique conceptualization of human structure and movement could be further expanded by incorporating insights from other disciplines. Loaded strenuous exercise can be a crucial tool to further enhance our clients’ newfound awareness for movement, especially when we manage to relate it to a meaningful sensorimotor context for them.
Strength training is safe and beneficial for healthy individuals of all age groups (Kittilsen et al. 2021). In case of particular health problems, any intervention must be revised individually. Training frequency and intensity are a particularly heated topic among sports physiologists and coaches. Any type of desired muscular adaptation (like increasing one’s muscle mass) needs an adequate frequency of training sessions per week. Two training sessions per week are sufficient to increase strength and muscle mass. Individuals over the age of sixty may benefit more from spreading the training volume over three to four days (Schoenfeld 2021).
Conclusion
As we have seen, the human body behaves differently when faced with high external and internal forces. Rolfers can support athletes and laborers in coping with those intensities in a unique way. Not only can we release excess tension in the tissues with our manual interventions, we additionally can also educate the nervous system of our clients to integrate the felt sensations into their movement routine. The heightened awareness of one’s own kinesphere (the three-dimensional spherical space the body occupies) and the resulting potential for action give the ability to integrate proprioceptive and interoceptive information more economically. These can be the result of a comprehensive Rolfing Ten Series.
The anatomical structures of interest in each of the ten sessions in a Rolfing Ten Series could be reevaluated in light of the client’s possible necessity to generate strength and power. The aforementioned myofascial peculiarities of the structures I mentioned and how they are more or less prone to respond under the influence of peak external perturbations could be part of a broader view of the anatomical landmarks that Rolfers attend to during the Ten Series.
Furthermore, the Rolfing-specific conceptualization of movement could be revised, opening it up to include movements that are fast and powerful. Godard’s contribution to Rolfing Structural Integration is unique in its approach, as it bridges movement and meaning. But, clients requiring more strenuous movement will anticipate ‘space as the potential for action’ according to their individual context. Besides Godard’s conceptualization, other hypotheses and theories about motor learning describe strength and power more comprehensively and should be considered.
At last, as Rolfers, we must not forget the physical demands of numerous occupations. Having a clear understanding of how to generate strength in a specific context can be beneficial for both laborers and athletes. As Rolfers, we would miss out on the specific needs of people with physically demanding jobs, athletes, and tradespeople, who may or may not be people who regularly visit the gym. More research is needed to understand the effects that a Rolfing Ten Series may have on speed and strength training. There are great opportunities for Rolfing Structural Integration to further develop when we manage to open up to the insights of other movement-related disciplines and start to be more critical of our own principles.
Endnotes
1. The epimysium, the outermost layer that is a sheath around the entire muscle; the perimysium, connective tissue that covers each fasciculus; and the endomysium that is the innermost sheath covering individual muscle fibers (Heeransh, Shook, and Varacallo 2023).
2. Alpha motor neurons play a crucial role in transmitting signals from the motor cortex and spinal interneurons to the muscles. Gamma motor neurons regulate the stretch reflex by adjusting the level of tension in the intrafusal muscle fibers of the muscle spindle.
3. Intrafusal structures are mechanoreceptors within the muscle, while extrafusal muscle fibers are the large and numerous fibers that generate almost all the muscle tension produced during locomotion and maintenance of posture (Walro and Kucera 1999).
For his whole life, Jakob Reichardt has been about movement and sport. From his recreational sports to his competitive accomplishments, he has been fascinated by the anatomy, physiology, and biomechanics of the human body. Learning Rolfing Structural Integration gave him the theoretical understanding of how to practice his athletics in a way that was more intelligent and had a positive and lasting impact on his body and well-being, both in sports and in everyday life. Being a Rolfer has allowed Reichardt to collaborate with his clients, whether they be competitive athletes, craftspeople, or office workers, to support balance in his or her posture and personal exercise routines. Starting out as a personal trainer, in 2018, he completed his Bachelor of Sports Sciences from the Technical University of Munich (TUM), and in 2021 became a Certified Rolfer. He practices in Munich, Germany. See www. rolfingreichardt.com for more information.
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Rolfing Structural Integration; gravity; sensorimotor feedback; force; strength; kinetics; myofascia; fascia; sarcomere; Hill model; peak isometric forces; reflex arcs; muscle spindles; Golgi tendon organs; proprioceptors; attractors; fluctuators; co-contractions; biarticular muscles; pre-flexes; high impact movement; hamstring tension; neuromuscular testing; motor learning; fascia remodeling; mechanotransduction; strength training. ■
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