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Background and Purpose: Sarcopenia is a common muscle disease among the older population, posing an increased risk for functional decline and loss of independence in daily living. Early detection of sarcopenia among older people before functional decline would be beneficial in enhancing their quality of life. The Asian Working Group for Sarcopenia (AWGS) 2019 recommends the use of 3 screening methods for community-based sarcopenia detection: calf circumference (CC), or the Strength, Assistance in walking, Rise from a chair, Climb stairs, and Falls (SARC-F) questionnaire, or the SARC-F in combination with CC (SARC-CalF) questionnaire. This study aims to compare the relative performance of these 3 methods as screening tools for sarcopenia within a community-dwelling older population. Methods: A total of 700 community-dwelling older adults participated in the current study. Muscle mass, muscle strength, and physical performance were measured with bioelectrical impedance analysis, handgrip strength, and gait speed, respectively. The AWGS 2019 criteria were considered the criterion standard The sensitivity/specificity, receiver operating characteristic (ROC) curve, and area under the receiver operating characteristic curve (AUROC) analyses were determined for CC, SARC-F, and SARC-CalF to determine their relative diagnostic performance. Results: Sarcopenia was identified in 21.4% of participants according to the AWGS2019 criteria. The overall prevalence of sarcopenia was 56.6%, 14.7%, and 22.9% according to CC, SARC-F, and SARC-CalF, respectively. Calf circumference showed the highest sensitivity but lowest specificity based on AWGS 2019 as the criterion standard regardless of age, gender, and body mass index. The SARC-CalF showed better sensitivity but similar specificity than the SARC-F. The AUROC of CC was significantly better than that of SARC-F and SARC-CalF. The AUROCs of CC, SARC-F, and SARC-CalF were statistically significant in all populations, as well as in the categories of age, gender, and body mass index (P < .05). Conclusions: Calf circumference is useful in ruling out the presence of sarcopenia while the SARC-F is more effec-tive in ruling in sarcopenia, especially in the context of population-based screening. Future studies should be carried out to investigate the value of population-based sarcopenia detection using these screening tools. [ABSTRACT FROM AUTHOR]

Background The Y-Balance Test (YBT), especially the posteromedial (PM) reach direction (PM-YBT), is able to identify dynamic postural control deficits in those who have ankle instability. However, there still exists a need to understand how sensorimotor function at the ankle explains the performance during the PM-YBT. Hypothesis/Purpose The purpose of this study was to determine whether the ability to accurately control eccentric ankle torque explained PM-YBT performance. It was hypothesized that eccentric dorsiflexion/plantarflexion torque control would be positively related to the maximum reach distance (MRD) of PM-YBT. Study Design Cross-sectional study Methods Twelve healthy subjects performed the PM-YBT, maximum voluntary isometric contractions (MVIC) for both dorsiflexion and plantarflexion muscle strength, and then the torque control testing of the ankle. The torque control testing provided a target torque level on a screen in front of the subject and passive rotations of the ankle joint in the sagittal plane at 10 deg/sec between plantarflexion to dorsiflexion. Subjects were then instructed to eccentrically contract the dorsiflexors and plantar flexors to generate torque while the ankle joint rotated. The accuracy of torque control during eccentric dorsiflexion and plantarflexion by calculating absolute errors, the area between the target torque and the produced torque were evaluated. Tibialis anterior and soleus muscle activities were simultaneously recorded during testing. A step-wise linear regression model was used to determine the best model predicted the MRD of the PM-YBT (PM-MRD). Results A step-wise linear regression developed a model explaining only eccentric dorsiflexion torque control predicted higher PM-MRD score (R² = 44%, F1,10 = 7.94, β = -0.67, p = 0.02). Conclusion The accuracy of torque control during eccentric dorsiflexion predicts better performance in the PM-YBT. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the effect of dry needling (DN) with 44°C heating on the pressure pain threshold (PPT) of rats with chronic myofascial pain syndrome (MPS) by regulating the transient receptor potential V1 channel. A total of 80 rats were divided into 5 groups: A, B, C, D, and E (16 in each group). The rats in Group A recovered naturally, while those in other groups received the DN treatment. The needles were heated to 40°C for the rats in Groups B and E and 44°C for the rats in Groups C and D. In addition, both Groups D and E received local capsaicin injection. PPTs of the gastrocnemius muscle and tolerance time of the plantar hot plate were measured before modeling, 1 day before the intervention, 24 hours after the intervention, and 7 days after the intervention. PPTs of the gastrocnemius muscle for rats with MPS increased 7 days after DN and heating to 40°C. For the rats receiving DN at 44°C heating, PPTs increased 24 hours and 7 days after the intervention. Further, 44°C heating and capsaicin injection improved PPT. DN and 40°C heating followed by capsaicin injection improved PPT. DN and 44°C heating had therapeutic effects on rats with MPS at 24 hours and at 7 days after the intervention. DN and 40°C heating had therapeutic effects 7 days after the intervention. DN and 44°C heating might exert therapeutic effects by regulating the transient receptor potential V1 channel. [ABSTRACT FROM AUTHOR]

Background: In self-ankle mobilization with movement (S-MWM) therapy, a strap can be utilized to stabilize the posterior glide of the talus during ankle dorsiflexion movements. Objectives: Our objective was to compare the effects of 4-week self-mobilization with movement (S-MWM) with those of calf muscle stretching (CMS) on ankle dorsiflexion passive range of motion (DF-PROM), gait parameters, and fall risk in patients with chronic stroke with limited ankle dorsiflexion. Methods: Participants were randomized into the S-MWM (n = 19) and CMS groups (n = 19). Both groups received conventional physiotherapy for 30 minutes per session. In addition, S-MWM and CMS techniques were performed 3 times per week for 4 weeks and were performed by the participants themselves. Ankle DF-PROM, gait parameters, and fall risk were measured after 4 weeks of training. Results: After 4 weeks of training, both groups showed significant improvement in all outcome measures (p <.05). Furthermore, ankle DF-PROM, gait parameters (gait speed, cadence, and stride lengths on both sides), and fall risk showed greater improvement in the S-MWM group than in the CMS group (p <.05). Conclusions: This study shows that S-MWM training combined with conventional physiotherapy improved ankle DF-PROM, gait parameters, and fall risk in patients with chronic stroke. [ABSTRACT FROM AUTHOR]

Background: Performing physical activities on compliant surfaces alters joints kinematics by decreasing joint motions. However, the effect of administering a training program on a compliant surface on muscle activities after anterior cruciate ligament (ACL) injury is unknown. Hypothesis/Purpose: To compare the effects of training on a compliant surface and manual perturbation training on individual muscle activation and muscle co-contraction indexes after an ACL injury. It was hypothesized that patients who received training on the compliant surface would demonstrate higher individual and combined muscle activities compared to the manual group. Method: Sixteen patients (participated in level I/II sports) who sustained an ACL injury and had not undergone reconstructive surgery participated in this preliminary study. Eight patients received training on a compliant surface (Compliant group) and data of eight patients matched by age and sex from a previous study who received manual perturbation training were used as a control group (Manual group). Patients in both groups completed standard three-dimensional gait motion analysis with surface electromyography (EMG) of several lower extremity muscles during gait. Muscle co-contraction index and individual muscle activations were computed during weight acceptance (WA) and mid-stance (MS) intervals. A 2x2 analysis of variance (ANOVA) was used with an alpha level of p<0.10 to account for the high EMG variability. Results: The compliant group significantly increased muscle co-contraction of vastus lateralis-lateral hamstring (VL-LH), vastus medialis-gastrocnemius medialis (VM-MG), and vastus lateralis (VL) muscle activity during WA (p ≤ 0.035) and manual group significantly decreased VM-MG muscle co-contraction during WA (p=0.099) after training. Conclusion: Administering training on a compliant surface provides different effects on muscle activation compared to manual perturbation training after an ACL injury. Training on a compliant surface caused increased muscle co-contraction indexes and individual muscle activation, while manual perturbation training decreased the VM-MG muscle co-contraction index. Level of evidence: 2b [ABSTRACT FROM AUTHOR]

Background: Statins therapy is effective in the prevention of cardiovascular events. However, its use is associated with skeletal muscle myopathy, which may be severe enough to discontinue statin therapy, thus exposing patients to more morbidity and mortality. This study was conducted to assess the effect of L-carnitine on the skeletal muscle contractility in a rat model of statin-induced myopathy and to clarify its possible mechanisms. Methods: Twenty-one female Sprague Dawley rats were used throughout this study. The rats were divided into the normal control group, statin-induced myopathy group and statin/L-carnitine-treated group. The assessment of gastrocnemius muscle contractility, plasma creatine kinase (CK) levels and oxidative stress markers (malondialdehyde, reduced glutathione) was also carried out done. Results: The results of the current study suggest that simvastatin decreased the skeletal muscle mass and altered the muscle contractile properties. It also significantly increased plasma CK level and induced a state of oxidative stress state (high MDA, low GSH). Meanwhile, concurrent L-carnitine significantly reduced statin-induced myopathy and improved the oxidative stress markers and skeletal muscle contractile parameters. Conclusions: Statin myopathy is postulated to be due to mitochondrial dysfunction, cellular oxidative stress, induction of apoptosis, reduction in the expression of chloride channel and its related conductance, in addition to the alteration of Ca2+ homeostasis. L-carnitine has an antioxidant effect, reduces skeletal muscle atrophy and improves the skeletal muscle contractility in simvastatin-induced myopathy. [ABSTRACT FROM AUTHOR]

Background: Dry needling (DN) has been established as an effective treatment for myofascial pain, however, there are no studies thus far investigating the benefit to movement and motor control. Purpose: The primary purpose of this study was to compare differences in a series of outcomes between dry needling, dry needling and stretching, and stretching only in a sample of healthy males. A secondary purpose was to compare change over time. Design: Blinded, randomized controlled trial Methods: Thirty healthy male subjects were randomly assigned to one of three intervention groups: DN, stretching, or combination DN +stretching. Subjects in the DN group and DN+stretch group received DN to a palpated trigger point (TrP) in the triceps surae to elicit local twitch response. Subjects in the stretch group and DN+stretch group were instructed in a home stretching program for gastrocnemius and soleus muscles. All groups were tested for dorsiflexion range of motion and performed functional tasks (overhead deep squat, and Y-Balance test, Lower Quarter) prior to intervention, directly after intervention, and four days post intervention. Group comparisons were performed using a repeated measure Analysis of Variance and a partial eta squared calculation for effect size. For all measures a p-value of <0.05 was used to determine significance. Cohen's criteria were used to categorize strength of effect size. Results: There were no statistically significant differences among groups for range of motion nor functional measures, with the exception of the deep squat. Proportionally, the DN group improved significantly in deep squat performance (p<0.01) compared to the other groups. Time oriented improvements were seen for the YBT posterior-lateral reach (p=0.02) only. Between groups effect sizes ranged from 0.02 (small) to 0.17 (large). Conclusions: Including DN did not markedly influence range of motion nor functional assessment measures, excluding those seen during the overhead deep squat. Effect measures suggest the lack of significant findings may be an issue of statistical power. Level of Evidence: 1b [ABSTRACT FROM AUTHOR]

Background: The gastrocnemius has two heads, medial gastrocnemius (MG) and lateral gastrocnemius (LG); little is known how they contract with different foot positions. The MG is more frequently strained than the LG; and gastrocnemius activation pattern altered by foot position may play a role in injury. Leg exercises often use a toe-in versus toe-out foot position to isolate one gastrocnemius head over another. Purpose: The purpose of this study was to determine the electromyographic gastrocnemius muscle activity in the toe-out and toe-in foot positions during weight bearing and non-weight bearing activities. The hypothesis was that a toe-out foot position would elicit greater MG than LG activity; while the toe-in position would elicit greater activity in LG than MG in both weight bearing and non-weight bearing (NWB) positions. Study Design: A cross-sectional study of young adults. Methods: Thirty-three participants were recruited. Surface electrodes were placed on the bellies of the MG and LG. The gastrocnemius muscle was tested in toe-in and toe-out foot positions using two different tests: a standing heel-rise and resisted knee flexion while prone. Electromyographic activity was normalized against a MVIC during a heel raise with a neutral foot position. A 2x2x2 (Foot Position x Test Position x Muscle) ANOVA was used to determine if differences exist in activity between the MG and LG for toe-in versus toe-out standing and prone test positions. Results: Significant test position main effect (F [1,32] = 86.9; p < .01), significant muscle main effect (F [1,32]=5.5; p < .01), and significant foot position x muscle interaction (F [1,32] = 14.58; p < .01) were found. Post hoc tests showed differences between MG and LG in toe-out position (t = 3.10; p < .01) but not in the toe-in for both test positions (t = 1.27; p= 0.21). Conclusions: With toe-out, the MG was more active than LG in standing and prone; no difference was noted between MG and LG in toe-in for either position. [ABSTRACT FROM AUTHOR]

Background: Instrument-Assisted Soft Tissue Mobilization (IASTM) is a non-invasive therapeutic technique used to theoretically aid in scar tissue breakdown and absorption, fascial mobilization, and improved tissue healing. Researchers have hypothesized that utilizing IASTM will improve muscular efficiency and performance; yet previous Investigations has been focused on treating injury. Objective: The purpose of this investigation was to explore the effects of IASTM on muscle performance to assess if typical treatment application affected measures of muscular performance. Design: A pretest-posttest randomized control design. Participants: A convenience sample of 48 physically active adults (mean age 24±4 years), randomly assigned to one of three groups: quadriceps treatment group, triceps surae treatment group, or control group. Interventions: Participants performed a five-minute warm-up on a Monark bicycle ergometer before performing three countermovement vertical jumps (CMJ). Immediately after, the IASTM treatment was applied by one researcher for three minutes on each leg at the specified site (e.g., quadriceps) for those assigned to the treatment groups, while the control group rested for six minutes. Immediately following treatment, participants performed three additional CMJs. Pre- and post-testing included measures of vertical jump height (JH), peak power (PP) and peak velocity (PV). Results: There were no statistically significant differences found between treatment groups in JH, PP, or PV or across pre- and post-test trials. Conclusions: These preliminary findings suggest that standard treatment times of IASTM do not produce an immediate effect in muscular performance in healthy participants. This may help clinicians determine the optimal sequencing of IASTM when it is part of a pre-performance warm-up program. Future research should be conducted to determine the muscle performance effects of IASTM in individuals with known myofascial restriction and to determine optimal treatment parameters, such as instrument type, amount of pressure, and treatment time necessary to affect muscular performance. Level of Evidence: 1b [ABSTRACT FROM AUTHOR]

Patellofemoral disorders, commonly encountered in sports and orthopedic rehabilitation settings, may result from dysfunction in patellofemoral joint compression. Osseous and soft tissue factors, as well as the mechanical interaction of the two, contribute to increased patellofemoral compression and pain. Treatment of patellofemoral compressive issues is based on identification of contributory impairments. Use of reliable tests and measures is essential in detecting impairments in hip flexor, quadriceps, iliotibial band, hamstrings, and gastrocnemius flexibility, as well as in joint mobility, myofascial restrictions, and proximal muscle weakness. Once relevant impairments are identified, a combination of manual techniques, instrument-assisted methods, and therapeutic exercises are used to address the impairments and promote functional improvements. The purpose of this clinical commentary is to describe the clinical presentation, contributory considerations, and interventions to address patellofemoral joint compressive issues. [ABSTRACT FROM AUTHOR]

Background: Falls are the number 1 cause of injury, fractures, and death among the older population. In fact, one-third of adults older than 60 years will experience 1 or more falls annually. Factors including inactivity and decreased mobility are associated with overall declines in strength, balance, and functional mobility in older adults. Purpose: The purpose of this study was to evaluate the effect of a balance training program, including calf muscle strengthening, in community-dwelling older adults and to evaluate how calf muscle strength correlates with risk factors for falls. Methods: Community-dwelling older adults from a local senior center were invited to participate in a 5-week (10 sessions), 1-on-1, balance training program, which included calf muscle strengthening. All the participants were evaluated before and after the intervention. The outcome measures were static balance, unilateral heel-rise test, Timed Up and Go test (TUG), the 30-second Chair Stand Test (30-sCST), and the Activity Balance Confidence Scale. Results: Twenty-eight participants (6 males and 22 females) mean (standard deviation) age of 78 years were included in the study and completed the baseline evaluation. Eight participants did not complete the study. Static balance with eyes closed, heel rise, TUG, 30-sCST, and the Activity Balance Confidence Scale improved significantly (P < .05) following treatment compared with the baseline evaluation. The heel-rise ability correlated significantly (P < .05) with TUG (r = -0.484 to -0.528) and 30-sCST (r = 0.501-0.595). Sixty-three percent of the participants performed 10 reps or less of the unilateral heel rise on the right side and 60% on the left side. None of the participants who performed 10 reps or more of the unilateral heel rise had a high risk of falls based on the TUG. Conclusions: A balance training program that includes calf muscle strengthening performed twice a week for 5 weeks resulted in significant improvements in calf muscle strength, functional performance and balance, as well as a significant improvement in balance confidence. The results from this study identify the importance unilateral calf muscle strength has to falls risk among older adults. [ABSTRACT FROM AUTHOR]

The purpose of this study was to determine the effects of 6-week plyometric training on vertical jump performance and electromyography (EMG) activities of vastus lateralis (VL), vastus medialis (VM), and gastrocnemius (GAS) muscles during countermovement jump (CMJ). Twenty-four highly physically active physical education students were randomly assigned either to a plyometric (PLY) group or a control group. The experimental group performed plyometric exercises 2 times a week for 6 weeks, whereas the control group participated only in their lectures. The results revealed that there were no significant changes in either vertical jump height or EMG activities of selected muscles for the control group (p greater than 0.05). However, after 6 weeks of plyometric training, significant improvements (p less than 0.05) were observed in EMG activities of VL (13.25%), VM (9.60%), and GAS (13.93%) muscles, and no significant increase (p greater than 0.05) was found in CMJ (2.77%) in the PLY group. In conclusion, the findings of the this study suggest that 6 weeks of PLY training, in addition to the regular academic program, induced significant improvements in EMG activities of lower extremity muscles but no significant increases in vertical jump height. Accordingly, PLY exercises are recommended as part of a regular academic program in order to increase important components of athletic performance for physical education students. [ABSTRACT FROM AUTHOR]

The article investigates extensibility changes in the gastrocnemius muscle (GM), muscle-tendon unit, and the Achilles tendon (AT) in terms of maximum ankle dorsiflexion (max-DF) following a foam rolling intervention.

Background. In most studies on cardiovascular system, testing of subjects was performed in a horizontal position. With the change of the body position, certain functional changes occur in the cardiovascular system. The aim of this study was to analyze the effect of electrical muscle stimulation (EMS) on arterial and venous blood flows. Methods. Eighteen athletes aged 19-23 performed two sessions of tests in horizontal and sitting positions. Changes in arterial and venous blood flows were recorded before and after EMS. In each session two occlusions were performed. In the horizontal position, the initial occlusion pressure of 20 mmHg was applied and as the balance in arterial and venous blood flow rates was reached, the additional pressure of 20 mmHg (40 mmHg in total). In the sitting position, the occlusion pressure of 40 and 20 mmHg was applied respectively (60 mmHg in total). In both sessions EMS was performed using the electrical stimulator Mioritm 021. Results. In both horizontal and vertical positions, the effect of EMS on arterial blood flow, venous reserve capacity and venous elasticity was insignificant. Arterial and venous blood flows was affected significantly by the change of the body position. In the sitting position, arterial blood flow was significantly (p < .05) lower compared to the horizontal position. Similar results were recorded in venous reserve capacity. Conclusion. The study suggests that blood flow in the calf muscles is affected by the body position and hydrostatic pressure; arterial blood flow increases in the horizontal body position. [ABSTRACT FROM AUTHOR]

The article investigates the components of the physical demands placed upon the body during elite trampoline performance. Jumping on a stable surface has been a fundamental component of strength and conditioning for many years due to its application in many sporting activities as well as in very jumping-specific sports. General principles from this specialist area of strength and conditioning suggest the ability to master and maximise the potential of the surface on which the sport is being performed is fundamental and will impact on the outcome of the performance. Analogies can be drawn from other sports such as track and field where a significant amount of training and coaching time is spent teaching the athlete how to use the ground/surface effectively to generate and maximise forces. The obvious difference with trampolining is the surface on which the jumping is taking place. The large surface area of the trampoline bed, and the depression and recoil of its elastic components places new challenges on the body. Approximate force measurements from a pilot study into the physical demands of elite trampolining recorded loads of up to thirteen times body weight for high jumping. How can strength and conditioning aid the performance of this action, the repetition of such loads and overall performance? This article explores the concepts of jumping and landing in relation to mechanical efficiency and central nervous system demands. There are suggestions for challenging the physical components of human performance to ensure sufficient proactive injury prevention and ultimately improving performance. The reader will begin to think about the impact of surfaces, central nervous system response and general training principles around jump training [ABSTRACT FROM AUTHOR]

Brief information of the article "Lack Of Neuromuscular Origins Of Adaptation After A Long-Term Stretching Program," BT Hayes and A Rod is provided along with a link to its online abstract and the journal's comment on it.