Exercise Professional Education

11/04/2025

Rate of Force Development as a key physiological indicator of health...

“Explosive strength is the ability to increase force or torque as quickly as possible during a rapid voluntary contraction realised from a low or resting level. Rate of force development (RFD), which is derived from the force- or torque-time curves recorded during explosive voluntary contractions (Aagaard et al. 2002a)—hereafter also referred to as rapid or ballistic actions—is increasingly evaluated to characterise explosive strength of athletes, elderly individuals and patients. This is mainly due to the facts that, as compared to pure maximal voluntary contraction (MVC) strength, RFD seems to be (1) better related to most performances of both sport-specific and functional daily tasks (see, e.g., Maffiuletti et al. 2010; Tillin et al. 2013a), (2) more sensitive to detect acute and chronic changes in neuromuscular function (see, e.g., Angelozzi et al. 2012; Crameri et al. 2007; Jenkins et al. 2014b; Penailillo et al. 2015) and (3) potentially governed by different physiological mechanisms (see, e.g., Andersen and Aagaard 2006; Van Cutsem et al. 1998). The ability to properly quantify and interpret RFD obtained during voluntary isometric contractions is therefore extremely important not only for researchers in the field of human and exercise physiology, but also for practitioners in the fields of physical training and rehabilitation.”

Maffiuletti NA, Aagaard P, Blazevich AJ, Folland J, Tillin N, Duchateau J. Rate of force development: physiological and methodological considerations. Eur J Appl Physiol. 2016 Jun;116(6):1091-116. doi: 10.1007/s00421-016-3346-6. Epub 2016 Mar 3. PMID: 26941023; PMCID: PMC4875063.

10/28/2025

Interesting article: Scapular kinematics and task specificity: The effect of load direction

“Abstract
Our current understanding of healthy scapula motion is mainly based on studying the shoulder when it is generating an abduction torque against gravity. However, the shoulder can perform diverse tasks beyond abduction. In particular, little attention has been given to how scapula motion contributes to concentric adduction despite its involvement in high-demand tasks such as rock climbing and wheelchair transfers. Investigating scapular kinematics during concentrically loaded arm-lowering can provide insight into the mechanical demands underlying healthy scapula motion. In this study, we combined biplanar videoradiography and optical motion capture with a controllable cable machine to compare the three- dimensional humerothoracic, glenohumeral, and scapulothoracic kinematics between a weighted pull-down task (involving concentric shoulder adduction) and a weighted press-up task (involving concentric shoulder abduction) in ten healthy adults. We observed significantly more scapulothoracic upward rotation and less glenohumeral abduction during concentric adduction than concentric abduction. Our findings indicate that scapula upward rotation is not simply a function of overall humerothoracic elevation, but instead varies in a load-specific manner – potentially to orient the glenoid in a way that facilitates glenohumeral joint stability. We also observed substantial inter-individual variability in scapular kinematics within a task, and in how individuals responded to the different tasks. Our findings help provide a more well-rounded understanding of healthy scapular kinematics such that we can better identify and treat unhealthy motion (i.e., dyskinesis). Our findings can also inform musculoskeletal models that simulate scapulothoracic kinematics.”

E.C.S. Lee, N.M. Young, R.L. Lawrence, M.J. Rainbow, Scapular kinematics and task specificity: The effect of load direction, Journal of Biomechanics (2025), doi: https://doi.org/10.1016/j.jbiomech. 2025.112932

10/21/2025

10/20/2025

Greg discussing how emotional responses to injuries change the motor output of an injured region let alone the whole body. Why does an individual move the way they do? Better do your homework! The initial interview combined with a thorough assessment of motor expression combined with how they think and feel about moving and holding positions is key to the interpretation of observations.

Exercise Professional Education - think outside the box!

10/14/2025

Age and recovery

"Old people (> 60 yrs old) respond differently to strength training compared to young people. One feature is their ability to recover from exercise. Animal models have shown that old subjects display more muscle damage in response to a workout of eccentric contractions compared to young subjects. This appears to be caused by their muscle fibers having reduced capacity for lateral force transmission (due to a loss of dystrophin), leading to overstretching of the muscle fibers. Yet, human studies do not always report that old people display more post-workout fatigue than young people. This observation can likely be attributed to their lower levels of motor unit recruitment (indeed, the fast twitch muscle fibers of the highest-threshold motor units are the most vulnerable to damage). Even so, recovery rates post-workout are much slower in elderly people (even when exactly the same amount of fatigue is experienced immediately after exercise). This indicates that the repair and regeneration processes that facilitate recovery from post-workout fatigue are less effective in elderly muscle tissue. In practice, this means that elderly lifters cannot make use of the same volume-frequency combinations as young lifters. Animal models have shown that while young subjects can recover from a given workout volume performed 3 times per week (and thereby make gains in strength and size), old subjects cannot recover from the same training program (and so do not make gains in strength or size). Yet, those same old subjects can make progress by doing the same workout volumes twice per week (or by doing lower workout volumes 3 times per week)."

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10/07/2025

Chronic Plantar Heel Pain is Principally Associated With Waist Girth (Systemic) and Pain (Central) Factors, Not Foot Factors: A Case-Control Study

"Objectives
To determine the independent associations of potential clinical, symptom, physical activity, and psychological factors with chronic plantar heel pain.

Design
Case-control.

Methods
We investigated associations by comparing 220 participants with chronic plantar heel pain (>3 months) and 100 age- and s*x-matched controls recruited randomly from the electoral roll. Exposures measured were waist girth, BMI, body composition, clinical measures of foot and leg function, physical activity by accelerometry, depression and pain catastrophising, symptoms of prolonged morning stiffness anywhere in the body, and multisite pain. Data were analysed using multivariable conditional logistic regression.

Results
Waist girth (cm) (OR 1.06; 95% CI 1.03 to 1.09), ankle plantarflexor strength (kg) (OR 0.98; 95% CI 0.97 to 0.99), pain at multiple sites (OR 2.76; 95% CI 1.29 to 5.91 (pain at 1 other site), to OR 10.45; 95% CI 3.66 to 29.81 (pain at 4 or more other sites)) and pain catastrophising status (none, some or catastrophiser) (OR 2.91; 95% CI 1.33 to 6.37 (some), OR 6.79; 95% CI 1.91 to 24.11 (catastrophising)) were independently associated with chronic plantar heel pain. There were univariable but not independent associations with morning stiffness, first metatarsophalangeal joint extension ROM, depression and BMI, and no significant associations with physical activity or body composition by bioimpedance analysis.

Conclusion
Waist girth, ankle plantarflexor strength, multisite pain and pain catastrophising, but not foot-specific factors, were independently associated with chronic plantar heel pain. Three of four of these factors reflect central or systemic associations."

J Orthop Sports Phys Ther, Epub 7 May 2021. doi:10.2519/jospt.2021.10018

09/30/2025

Deep and superficial cervical muscles respond differently to
unstable motor skill tasks

"A B S T R A C T
Biomechanical modelling and physiological studies suggest that various spinal muscle layers differ in their contribution to spine movement and stiffness. This study aimed to investigate the
activation of deep and superficial muscles in stable and unstable task conditions. Nine healthy participants performed a task of controlling a metal ball on a plate fixed to the head in seated
position. In unstable tasks, visual feedback was provided by mirrors to move the ball to the centre of the plate by small head movements and maintain the position for 3 s. Task difficulty was
adjusted in a stepwise progression of difficulty using five surfaces with materials of decreasing resistance. In the stable condition, the ball was fixed to the plate's centre. EMG was recorded with surface (sternocleidomastoid, anterior scalenes, upper trapezius) and fine-wire electrodes (re**us capitis posterior major, obliquus inferior, multifidus, semispinalis cervicis, splenius capitis). The outcome variable was root mean square (RMS) EMG during the part of the task when the ball was
maintained in the centre position. Results revealed greater cervical muscle activity in the unstable than stable conditions (p

09/29/2025

The first ever MSS Full Immersion Experience Course is in the books. Great group of passionate and dedicated professionals paving the way for out of the box problem solving! 🔥

09/27/2025

A great day of problem solving turned into an even better night of company!

An incredible dinner in Columbus, OH with the crew in town for the MSS Full Immersion weekend at the office!

09/23/2025

Research: Olfactory function and motor function relationship? Apparently so…

“Abstract

Background: Among older adults, both olfaction and motor function predict future cognitive decline and dementia, suggesting potential shared causal pathways. However, it is not known whether olfactory and motor function are independently related in late life.

Methods: We assessed cross-sectional associations of olfaction with motor and cognitive function, using concurrent data on olfactory function, mobility, balance, fine motor function, manual dexterity, and cognition in 163 Baltimore Longitudinal Study of Aging participants aged 60 and older without common neurological diseases (n = 114 with available cognitive data). Using multiple linear regression, we adjusted for age, s*x, race, smoking history, height, and weight for mobility and balance, and education for cognition. We used multiple linear regression to test whether olfaction-motor associations were independent of cognition and depressive symptoms.

Results: Olfactory scores were significantly associated with mobility (usual gait speed, rapid gait speed, 400-m walk time, and Health ABC Physical Performance Battery score), balance, fine motor function, and manual dexterity (all p < .05). In those with available cognitive data, additional adjustment for depressive symptoms, verbal memory, or visuoperceptual speed demonstrated especially strong independent relationships with challenging motor tasks such as 400-m walk and nondominant hand manual dexterity (p < .005)

Conclusions: This study demonstrates for the first time that, in older adults, olfactory function is associated with mobility, balance, fine motor function, and manual dexterity, and independent of cognitive function, with challenging upper and lower extremity motor function tasks. Longitudinal studies are needed to determine if olfactory performance predicts future mobility and functional decline.”

Tian Q, Resnick SM, Studenski SA. Olfaction Is Related to Motor Function in Older Adults. J Gerontol A Biol Sci Med Sci. 2017 Aug 1;72(8):1067-1071. doi: 10.1093/gerona/glw222. PMID: 27811155; PMCID: PMC5861968.

09/02/2025

Individuals with chronic low back pain have reduced myofascial force transmission between the latissimus dorsi and contralateral gluteus maximus muscles

“Abstract
The thoracolumbar fascia is essential in lumbar stabilization and is considered a path of transmitting myofascial force. This study investigates whether there is a difference in the myofascial force transmission between latissimus dorsi and contralateral gluteus maximus in individuals with and without chronic low back pain (CLBP). Forty-eight individuals were divided into CLBP and control groups. Outcome variables were evaluated in two experimental conditions: relaxed and contracted latissimus dorsi. Lumbar stiffness was assessed using a non-invasive digital indentometer, and passive properties of the contralateral hip (resting position, torque and stiffness) were evaluated using an isokinetic dynamometer. Trunk and hip muscle activation was monitored with electromyography. Data were analyzed using two-way ANOVA. Latissimus dorsi contraction increased lumbar stiffness in both groups (p < 0.001) compared to the relaxed condition. However, only the control group showed a change in the hip resting position toward greater lateral rotation and an increase in passive hip torque with latissimus dorsi contraction compared to the relaxed condition (p < 0.001). Additionally, latissimus dorsi contraction led to a small and clinically non-relevant increase in passive hip stiffness (below the standard error of measurement) in both groups when compared to the relaxed condition. The results demonstrated that the myofascial force transmission between latissimus dorsi and contralateral gluteus maximus is reduced in individuals with CLBP, since the latissimus dorsi contraction changed the passive properties only in the adjacent tissues (lumbar region) but not in tissues more distant from the origin of the traction.”

Paula R Soares Procópio, Rafael Zambelli Pinto, Bárbara A Junqueira Murta, Paola Figueiredo Caldeira, Priscila Albuquerque Araújo, Robert Schleip, Sérgio Teixeira Fonseca, Renan Alves Resende, Juliana Melo Ocarino, Individuals with chronic low back pain have reduced myofascial force transmission between latissimus dorsi and contralateral gluteus maximus muscles,
Journal of Biomechanics, Volume 190, 2025, 112850, SSN 0021-9290, https://doi.org/10.1016/j.jbiomech.2025.112850.