related to muscle hypertrophy. Determining if hypertrophy occurs after rehabilitation and if it may be responsible for increases in measured force will allow for more informed decisions regarding the prescription of therapeutic exercise for the treatment of LAS and CAI. Analyzing muscle morphological
Mark A. Feger, Luke Donovan, C. Collin Herb, Geoffrey G. Handsfield, Silvia S. Blemker, Joseph M. Hart, Susan A. Saliba, Mark F. Abel, Joseph S. Park and Jay Hertel
Camila Ximenes Santos, Natália Barros Beltrão, André Luiz Torres Pirauá, João Luiz Quagliotti Durigan, David Behm and Rodrigo Cappato de Araújo
Context: Although stretching exercises are commonly used in clinical and athletic practice, there is a lack of evidence regarding the methodological variables that guide the prescription of stretching programs, such as intensity. Objective: To investigate the acute effects of different stretching intensities on the range of motion (ROM), passive torque, and muscle architecture. Design: Two-group pretest–posttest design. Setting: Laboratory. Participants: Twenty untrained men were allocated into the low- or high-intensity group. Main Outcome Measures: Subjects were evaluated for initial (ROMinitial) and maximum (ROMmax) discomfort angle, stiffness, viscoelastic stress relaxation, muscle fascicle length, and pennation angle. Results: The ROM assessments showed significant changes, in both groups, in the preintervention and postintervention measures both for the ROMinitial (P < .01) and ROMmax angle (P = .02). There were no significant differences for stiffness and viscoelastic stress relaxation variables. The pennation angle and muscle fascicle length were different between the groups, but there was no significant interaction. Conclusion: Performing stretching exercises at high or low intensity acutely promotes similar gains in flexibility, that is, there are short-term/immediate gains in ROM but does not modify passive torque and muscle architecture.
Lindsey K. Lepley and Timothy A. Butterfield
Eccentric exercise is able to mechanically engage muscle, initiating strain-sensing molecules that promote muscle recovery by inducing beneficial adaptations in neural activity and muscle morphology, 2 critical components of muscle function that are negatively altered after injury. However, due to misinterpreted mathematic modeling and in situ and in vitro stretch protocols, a dogma that exposing muscle to eccentric exercise is associated with injury has been perpetuated in the literature. In response, clinicians have been biased toward using concentric exercise postinjury to improve the recovery of muscle function. Unfortunately, this conventional approach to rehabilitation does not restore muscle function, and reinjury rates remain high. Here, the authors present experimental evidence and theoretical support for the idea that isolated eccentric exercise is ideally suited to combat muscle inhibition and muscle strains and is an attractive alternative to concentric exercise.
Jennifer M. Dent, Cameron J.R. Blimkie, Colin E. Webber, Angus B. McMillan and Rhona M. Hanning
Absolute total body (TB) and regional spine (RS) bone mineral content (BMC) measured by dual photon absorptiometry were lower (p < .05) in Turner syndrome (TS) girls compared to a cohort of younger (by 2 years) but taller and heavier prepubertal girls. Maximal voluntary strength (MVC) of the elbow flexors, knee extensors, and plantar flexors were also consistently and, in most cases, significantly lower in TS girls. Differences between groups in absolute bone mineral and muscle strength disappeared, however, when normalized for skeletal cross-sectional area (areal density) and for the product of muscle cross-sectional area and estimated moment arm, respectively. Maximal voluntary strength and body mass correlated moderately strongly with the bone mineral measures, but only body mass contributed significantly to the variance in total body and regional spine bone mineral measures. Bone mineral and muscle strength appear appropriate for body size and for skeletal and muscle morphology in young TS girls.
Luke Van Wyk, Gwendolen Jull, Bill Vicenzino, Mathew Greaves and Shaun O’Leary
The purpose of this study was to compare maximal torque exerted about the craniocervical (CC) and cervicothoracic (CT) axes in the sagittal plane using a novel dynamometry device. Maximal voluntary contraction (MVC) recordings in newton-meters (N·m) were measured in 20 males and 20 females for each of 4 tests: CT extension, CT flexion, CC extension, CC flexion. Twenty of the volunteers repeated the testing procedure on a second occasion to determine the test–retest repeatability of the measures. MVC recordings at the CT axis (extension, 30.24 ± 12.15 N·m; flexion, 18.90 ± 8.21 N⋅m) were 1.4–2 times greater than recordings at the CC axis (extension, 16.46 ± 7.26 N⋅m; fexion, 13.34 ± 5.97 N·m). Extensor to flexor strength ratios reduced from 1.75 at the CT axis to 1.24 at the CC axis, but were similar for both males and females. Good to excellent test–retest repeatability was demonstrated for all tests (ICC = 0.75–0.99, SEM = 0.50–2.44 N·m). Consistent with differences in the muscle morphology at the CC and CT axes, torque exerted about these axes differ. Separate measurement of torque about these axes potentially offers a more comprehensive profile of cervical muscle strength.
Romuald Lepers, Paul J. Stapley and Thomas Cattagni
. Muscle strength and speed of movement in relation to age and muscle morphology . J Appl Physiol Respir Env Exerc Physiol . 1979 ; 46 ( 3 ): 451 – 456 . PubMed doi:10.1152/jappl.1918.104.22.1681 7. Grimby G , Saltin B . The ageing muscle . Clin Physiol . 1983 ; 3 ( 3 ): 209 – 218 . PubMed doi:10
Annika Kruse, Christian Schranz, Martin Svehlik and Markus Tilp
aged 2 to 5 years with cerebral palsy . Dev Med Child Neurol . 2011 ; 53 ( 6 ): 543 – 8 . PubMed ID: 21506995 doi:10.1111/j.1469-8749.2011.03913.x 10.1111/j.1469-8749.2011.03913.x 21506995 4. Barrett RS , Lichtwark GA . Gross muscle morphology and structure in spastic cerebral palsy: a
Conall F. Murtagh, Christopher Nulty, Jos Vanrenterghem, Andrew O’Boyle, Ryland Morgans, Barry Drust and Robert M. Erskine
, rate of force development; nRFD, rate of force development normalized to MVF. *Elite significantly greater than nonelite ( P < .05). Table 2 Quadriceps Femoris Muscle Morphology and Architecture in Elite (n = 23) and Nonelite (n = 20) Players, Mean (SD) Muscle variable Elite Nonelite Quadriceps
Emily R. Hunt, Shelby E. Baez, Anne D. Olson, Timothy A. Butterfield and Esther Dupont-Versteegden
, 34 Massage used for treatment of musculoskeletal injury has the ability to not only induce changes to muscle morphology, including alterations in muscle size and function, but can also benefit the patient by decreasing their pain and anxiety. Clinical Application Chronic pain is a difficult
Grant E. Norte, Katherine R. Knaus, Chris Kuenze, Geoffrey G. Handsfield, Craig H. Meyer, Silvia S. Blemker and Joseph M. Hart
rehabilitation. Peripheral changes in skeletal muscle morphology and neural mechanisms within the central nervous system are reported to contribute to persistent muscle weakness. 19 Clinically based techniques that are used to assess muscle atrophy (eg, thigh circumference, real-time ultrasound) may provide