Immediate effects of two types of self-stretching on flexor digitorum longus and tibialis posterior muscle stiffness.

We investigated the immediate effects of two types of self-stretching methods to clarify their efficacy on flexor digitorum longue (FDL) and tibialis posterior muscle (TP) stiffness. In 'conventional self-stretching', the subject used the strength of their own hands to dorsiflex the toes and dorsiflex and evert the ankle. In 'weight-bearing stretching', the participants instead weight-bearing to facilitate the dorsiflexion.

Center of Pressure in Relation to Foot Morphology and Knee Symptoms in Older Women With Medial Knee Joint Deformity: A Cross-Sectional Study.

Objective: To examine the correlations amongst center of pressure (COP) trajectories, foot morphology, and knee symptoms in older women with medial knee deformity.

Design: This was a cross-sectional study.

Setting: Participants were recruited from 2 local orthopedic clinics.

Relationship Between the Flexion Torque of the First Metatarsophalangeal Joint and Intrinsic Foot Muscles Depends on the Ankle Joint Position.

Background: Clinicians and researchers are beginning to pay attention to the importance of the intrinsic foot muscles (IFMs). Among IFMs, the abductor hallucis (AbH) is associated with foot disorders. However, so far no method for assessing the strength of the AbH has been established.

Effects of High-Velocity Versus Low-Velocity Resistance Training on Muscle Echo Intensity in Healthy Young Women: A Randomized Controlled Trial.

Background: Improving muscle quality to prevent and treat muscle dysfunction is critical. However, effective measures to improve muscle quality remain poorly understood. We investigated the effects of high- and low-velocity resistance training (RT) on muscle quality, mass, and function before and after an 8-week intervention.

Intramuscular fat infiltration influences mechanical properties during muscle contraction in older women.

Although evidence suggests that intramuscular fat infiltration may influence muscle strength, the precise mechanisms remain unclear. This study aimed to determine whether intramuscular fat infiltration affects muscle mechanical properties during contraction and whether these mechanical properties mediate the relationship between intramuscular fat infiltration and muscle strength. Seventy-nine healthy older women aged 75.

Characteristics of upper limb mass, muscle CSA and stiffness in adolescent baseball players with and without elbow injury.

Since elbow injuries are common in adolescent baseball players, this study aimed to determine the relationship between musculoskeletal status and elbow injuries in 47 baseball players aged 12-14 years. Participants answered a questionnaire and had their general body measurements taken. Magnetic resonance imaging was used to evaluate muscle cross sectional areas (CSA) of the upper arm flexor and extensor muscles, and x-ray absorptiometry was used to determine the mass of the upper arm and the total mass of the forearm and hand.

Assessment of fore-, mid-, and rear-foot alignment and their association with knee symptoms and function in patients with knee osteoarthritis.

Objective: Hallux valgus, flatfoot, and rearfoot eversion are well-known major complications of knee osteoarthritis (OA). However, there is no consensus on the association between these foot malalignments and knee symptoms or function. Thus, this study aimed to examine the association between foot alignment and knee symptoms or function in patients with knee OA.

Effect of shod and barefoot running on muscle mechanical properties.

Background: Barefoot runners have a higher probability of lower leg and foot disorders compared to runners wearing traditional running shoes. However, the site of muscle stress due to barefoot running has not been reported. This study aimed to investigate the effects of shod and barefoot running on muscle mechanical properties.

Effective muscle elongation positions for the neck extensor muscles: An ultrasonic shear wave elastography study.

This study aimed to clarify the effective stretching positions for neck extensor muscles. Fifteen healthy men were measured shear moduli of the right neck extensor muscles using ultrasound shear wave elastography in following positions: rest (Rest), flexion (Flex), contralateral bending (Bend), flexion + contralateral bending (Flex → Bend), flexion + contralateral bending + contralateral rotation (Flex → Bend → ConRot), and flexion + contralateral bending + ipsilateral rotation (Flex → Bend → IpsRot). The increase in the shear modulus indicated a greater muscle elongation.

The relation between kinematic synergy to stabilize the center of mass during walking and future fall risks: a 1-year longitudinal study.

Background: Incorrect body weight shifting is a frequent cause of falls, and the control of the whole-body center of mass (CoM) by segmental coordination is essential during walking. Uncontrolled manifold (UCM) analysis is a method of examining the relation between variance in segmental coordination and CoM stability. However, no prospective cohort study has thoroughly investigated how variance in segmental configurations to stabilize the CoM relates to future falls.

Acute and Prolonged Effects of Stretching on Shear Modulus of the Pectoralis Minor Muscle.

Increased muscle stiffness of the pectoralis minor (PMi) could deteriorate shoulder function. Stretching is useful for maintaining and improving muscle stiffness in rehabilitation and sport practice. However, the acute and prolonged effect of stretching on the PMi muscle stiffness is unclear due to limited methodology for assessing individual muscle stiffness.

Force Generation on the Hallux Is More Affected by the Ankle Joint Angle than the Lesser Toes: An In Vivo Human Study.

The structure of the first toe is independent of that of the other toes, while the functional difference remains unclear. The purpose of this study was to investigate the difference in the force generation characteristics between the plantar-flexion of the first and second-fifth metatarsophalangeal joints (MTPJs) by comparing the maximal voluntary plantar-flexion torques (MVC torque) at different MTPJs and ankle positions. The MVC torques of the first and second-fifth MTPJs were measured at 0°, 15°, 30°, and 45° dorsiflexed positions of the MTPJs, and at 20° plantar-flexed, neutral, and 20° dorsiflexed positions of the ankle.

Optimum Angle of Force Production Temporarily Changes Due to Growth in Male Adolescence.

The peak increase in lean mass in adolescents is delayed from peak height velocity (PHV), and muscle flexibility temporarily decreases as bones grow. If the decrease in muscle flexibility is caused by muscle elongation, the relationship between the exerted torque and the joint angle could change in adolescents. The purpose of this study was to investigate the change in the optimum angle of force production due to growth.

Positional difference of malleoli-midpoint from three-dimensional geometric centre of rotation of ankle and its effect on ankle joint kinetics.

Backgrounds: Joint kinetic calculations are sensitive to joint centre locations. Although geometric hip and knee joint centre/axis are generally developed, the ankle joint centre (AJC) is conventionally defined as the midpoint between the malleolus lateralis and medialis (AJC) in most gait analyses.

Research Question: We examined the positional difference of the AJC from the geometric centre of rotation (AJC) and its effect on the ankle joint kinetics in representative human gaits.

The effect of hip flexion angle on muscle elongation of the hip adductor muscles during stretching.

In order to perform effective static stretching of the hip adductor muscles, it is necessary to clarify the position where the muscles are most stretched. However, the effective flexion angle in stretching for each adductor muscle remains unclear. The goal of this study was to investigate the effect of hip flexion angle on muscle elongation of hip adductor muscles during stretching.

Relationship Between Muscle Swelling and Hypertrophy Induced by Resistance Training.

Hirono, T, Ikezoe, T, Taniguchi, M, Tanaka, H, Saeki, J, Yagi, M, Umehara, J, and Ichihashi, N. Relationship between muscle swelling and hypertrophy induced by resistance training. J Strength Cond Res 36(2): 359-364, 2022-Muscle swelling immediately after resistance exercise may be induced by metabolic stress.

Effects of ankle position during static stretching for the hamstrings on the decrease in passive stiffness.

Static stretching is frequently performed to improve flexibility of the hamstrings, although the ankle position during hamstring stretching has not been fully investigated. We investigated the effects of ankle position during hamstring stretching on the decrease in passive stiffness. Fourteen healthy men performed static stretching for the hamstrings with the ankle dorsiflexed and plantar-flexed in a randomized order on different days.

The relation between limb segment coordination during walking and fall history in community-dwelling older adults.

Control of the swing foot during walking is important to prevent falls. The trajectories of the swing foot are adjusted by coordination of the lower limbs, which is evaluated with uncontrolled manifold (UCM) analysis. A previous study that applied this analysis to walking revealed that older adults with fall history had compensatorily great segment coordination to stabilize the swing foot during normal walking.

Menstrual cycle variation and gender difference in muscle stiffness of triceps surae.

Background: We aimed to investigate the menstrual cycle variation and the gender difference of the triceps surae muscle stiffness and passive stiffness of the ankle joint.

Methods: The subjects of the study included 12 healthy young women and 12 healthy young men. Shear elastic moduli of the lateral gastrocnemius, medial gastrocnemius, and soleus muscles were measured as an index of muscle stiffness using shear wave elastography.

The reliability of shear elastic modulus measurement of the ankle plantar flexion muscles is higher at dorsiflexed position of the ankle.

Background: Excessive stiffness of lower limb muscles is associated with sports injuries. Therefore, the identification of a reliable measurement of the shear elastic modulus of various ankle plantar flexion muscles is required to evaluate lower leg sports injuries. This study investigated the reliable measurement of the shear elastic modulus of the ankle plantar flexion muscles at different ankle positions.

Ankle and toe muscle strength characteristics in runners with a history of medial tibial stress syndrome.

Background: A high proportion of flexor digitorum longus attachment is found at the posteromedial border of the tibia, which is the most common location of medial tibial stress syndrome (MTSS). Therefore, plantar flexion strength of the lesser toes could be related to MTSS; however, the relationship between MTSS and muscle strength of the hallux and lesser toes is not yet evaluated due to the lack of quantitative methods. This study investigated the muscle strength characteristics in runners with a history of MTSS by using a newly developed device to measure the muscle strength of the hallux, lesser toes, and ankle.

Improvement in muscle strength with low-load isotonic training depends on fascicle length but not joint angle.

Introduction: In this study we investigate whether low-load isotonic training will elicit greater improvement in muscle strength at the same fascicle length, rather than at the same joint angle.

Methods: Sixteen healthy men (24.1 ± 2.

Clarification of functional differences between the hallux and lesser toes during the single leg stance: immediate effects of conditioning contraction of the toe plantar flexion muscles.

[Purpose] The purpose of this study was to determine the functional differences of the plantar flexion muscles of the hallux and lesser toes during the single leg stance by comparing postural sway in different conditioning contraction interventions. [Subjects] Thirty-four healthy, young males and females participated in this study. [Methods] The front-back and right-left direction components of maximal displacement and postural sway velocity during the single leg stance were measured in various conditioning contraction interventions for the plantar flexion muscles of the hallux or lessor toes.

Relationship between navicular drop and measuring position of maximal plantar flexion torque of the first and second-fifth metatarsophalangeal joints.

[Purpose] The purpose of this study was to determine the relationship between navicular drop and plantar flexion torque of the first and second-fifth metatarsophalangeal joints. [Subjects] Ten healthy young men participated in this study. [Methods] The Pearson product-moment correlation coefficient was calculated to determine the relationship between navicular drop and plantar flexion torque of the first and second-fifth metatarsophalangeal joints.