Isometric Muscle Strength Research Articles

Preoperative hip abductor strength predicts discharge destination after total hip arthroplasty.

This study aimed to clarify the association between preoperative physical function and discharge destination after total hip arthroplasty (THA). This retrospective study included patients who underwent primary unilateral THA for hip osteoarthritis. Preoperative physical function was assessed via maximal isometric muscle strength (hip abduction and knee extension) and comfortable walking speed. The patients were divided into two groups according to the discharge destination (home or transfer to other facilities). Multivariate logistic regression analysis was used to identify preoperative physical function associated with discharge destination. Of the 174 patients, 120 were discharged directly to home, and 54 were transferred to other facilities. Those transferred to other facilities were significantly older, more likely to live alone, and had a longer operation time. In addition, they demonstrated lower hip abductor strength on both sides and lower knee extensor strength on the operative side. Multivariate logistic regression analysis revealed that hip abductor strength on both sides, not knee extensor strength, was independently associated with the discharge destination. The largest area under the receiver operating characteristic curve was 0.668 for the hip abductor strength of the contralateral side. The optimal cutoff point was revealed to be 0.035 kgf·m/kg and 0.031 kgf·m/kg for the operative and contralateral sides, respectively. Preoperative hip abductor strength, particularly on the contralateral side with a cutoff value of 0.031 kgf·m/kg, could be a predictor of discharge destination after unilateral THA. Our findings would be useful in planning rehabilitation programs.

Investigating the Effects of Shockwave and Percussion Massage Gun on Subacute Myofascial Pain in Gasterocenemious Muscle

Introduction: Myofascial pain syndrome is a common musculoskeletal injury, especially among athletes, typically treated with symptomatic invasive and non-invasive methods. This study compares the effects of massage guns and radial extracorporeal shock wave therapies on myofascial pain syndrome symptoms in amateur athletes. Materials and Methods: In this clinical trial, 45 amateur athletes (18-30 years old) were recruited, who were randomly assigned to 15-member groups of shock wave, massage gun, and control (routine treatment included electrotherapy and stretching, which was applied on three groups). After initial evaluations of the pain intensity, pain pressure threshold (PPT), isometric muscle strength, and range of motion (ROM), the patients received single-session treatment and were immediately reassessed. Results: The results showed pain relief and improved PPT following shock wave plus routine treatment (P=0.03). The control group had less pain, while pain intensity and PPT did not change. The variables were not significantly different between the groups (P=0.12). Shock wave along with routine treatment increased plantar flexion ROM (P=0.00), unlike the massage gun. Additionally, dorsiflexion ROM (P=0.63) and maximal isometric gastrocnemius muscle strength (P=0.95) remained unchanged in all groups. Conclusion: One session of massage gun therapy immediately reduced gastrocnemius muscle pain, while it failed to change PPT, maximal isometric gastrocnemius muscle strength, or dorsiflexion and plantar flexion ROM. However, shock wave therapy immediately increased plantar flexion ROM and PPT, and reduced pain intensity. These modalities led to limited changes, suggesting the need for repeated sessions and supplementary treatments.

The strength of associations between ultrasound measures of upper limb muscle morphology and isometric muscle strength: An exploratory study.

Assessing upper limb muscle strength is important for understanding health outcomes, such as daily function and mortality. Ultrasound (US) is increasingly used to evaluate muscle health, but the relationship between its measures of morphology and isometric strength has not been thoroughly explored in upper limb muscles. The aim of this study was to evaluate the associations between US morphological measures and isometric strength in functionally relevant upper limb muscles in healthy adults. Twenty-four healthy volunteers (30.0 ± 10.8 years) underwent B-mode, axial US scans of the first dorsal interosseus (FDI), flexor pollicis longus (FPL), biceps brachii (BB), brachialis (BR), and triceps brachii lateral head (TB). Participants performed corresponding maximal voluntary contractions (MVC), including first digit distal phalanx flexion, second digit abduction, and elbow flexion and extension. US images were segmented to obtain maximal muscle thickness (MT) and cross-sectional area (CSA). Strong positive correlations were found between muscle strength and BB MT (r = .83; p < .001), BR CSA (r = .84; p < .001), and TB MT (r = .70; p < .001). Moderate positive correlations were found for strength and FDI CSA (r = .67; p < .001), FDI MT (r = .47; p < .05), FPL CSA (r = .54; p < .01), and FPL MT (r = .42; p < .05). No significant correlation was found between strength and BR MT (r = .16; p > .05). Our data showed moderate-to-strong associations between US muscle morphology and strength, suggesting that US is likely a good biomarker for strength. However, its use is not "one size fits all." Future investigations should continue to assess this relationship in different muscles and expand the generalizability to clinical populations.

The comparison of Pilates with cognitive functional therapy in adults with chronic neck pain: a protocol for randomized controlled trial

Background Chronic Neck Pain is one of the main musculoskeletal problems in the general population that negatively affects the lives of patients. Its treatment can include various treatment methods, such as Pilates and Cognitive Functional Therapy. The purpose of this research was to investigate the effectiveness of Pilates in relation to Cognitive Functional Therapy in people with Chronic Neck Pain. Methods This single-blind randomized controlled study included 60 patients with Chronic Neck Pain who were randomly divided into two groups (Group 1: Pilates, Group 2: Cognitive Functional Therapy). All patients will undergo 16 sessions over 8 weeks. Outcome measures (pain, disability, fear perception, functionality, quality of life, cervical range of motion, and neck muscle isometric strength) will be evaluated at baseline, at the end of the treatment (week 8) and three months after randomization (week 12). Outcome measures will be analyzed via random effects at the three assessment time points, and the interactions of the treatment groups with the assessment points will be included in the results of the fixed model. Discussion This is the first Randomized Controlled Trial to compare the effectiveness of Pilates and Cognitive Functional Therapy in patients with chronic neck pain. The results of this research will provide information on the effectiveness of each intervention separately and whether one of the two can outperform the other.

The association between hip adductor and extensor strength, and hip-related patient-reported outcomes in patients with longstanding hip and groin pain: an exploratory cross-sectional study

ObjectiveThe objective of this study was to assess the association between hip muscle strength and hip-related patient-reported outcome measures (PROMs) in patients with longstanding hip and groin pain (LHGP). DesignCross-sectional design SettingOrthopedic care ParticipantsEighty-one patients with LHGP were consecutively recruited Main Outcome MeasuresHip muscle strength was measured in adduction and extension. Hip-related PROMs was measured with the Copenhagen Hip and Groin Outcome Score (HAGOS) which includes six subscales (Symptoms, Pain, Activity in Daily Living (ADL), Physical Function in Sports and Recreation (Sport/Rec), Participation in Physical Activities (PA), and Quality of Life (QoL). Linear regression examined the association between hip muscle strength and each HAGOS subscale. ResultsGreater isometric hip muscle strength in adduction was associated with better HAGOS score for Pain and ADL (p≤0.037), but not for Symptoms, Sport/Rec, PA, or QoL (p≥0.154). Greater isometric hip muscle strength in extension was associated with better HAGOS score for Symptoms, Pain, and ADL (p ≤0.034), but not for Sport/Rec, PA, or QoL (p ≥0.084). ConclusionsIn patients with LHGP, greater isometric hip muscle strength seems to be associated with less symptoms and pain, and better function in ADL. No association was found for Sport/Rec, PA, or QoL.

Effects of Nordic Hamstring Exercise on knee joint muscle strength in adolescent soccer players. A pilot study

Objective: Given the emerging imbalances in knee stabilising muscle strength, the aim of the study was to determine whether performing a single NHE intervention would alter the isometric strength of the knee flexor muscles (HAM). Material and Methodology: A group of 56 players of a youth football team (age range 13-16 years), were recruited for a pilot study. The group involved healthy players, training football at the central junior level. After meeting the inclusion criteria inclusion, 32 players were enrolled into the study. Participants were randomly allocated to a study group (A) and a control group (B). In the study group, the intervention consisted of a single NHE exercise in the form of a two series of trunk slumps, eight repetitions each. The control group performed one series of of forward trunk bends, five repetitions each. Participants (group A and B) were tested on the ForceFrame platform before the procedure experiment and immediately after the intervention was performed. Maximum force of the knee extensors (QUAD) and knee flexors (HAM) was measured. Results: Statistical analysis of the results indicated that maximal HAM muscle strength increased after a single NHE intervention (p = 0.04) relative to the control group. At the same time, after the intervention, there was no increase in the strength of the Quadriceps muscles (extensors of the knee joint) relative to the control group. Conclusions: The results obtained indicate that a single performance of the NHE exercise has the effect of increase in the maximum isometric strength of the HAM muscles. This increase, although not statistically significant, correlated with no change in quadriceps muscle strength. The work is pilot study and further research may have benefits in maintaining the balance between the two muscle groups, i.e. HAM and QUAD, which contributes to the prevention of musculoskeletal injuries.

Improvements in upper extremity isometric muscle strength, dexterity, and self-care independence during the sub-acute phase of stroke recovery: an observational study on the effects of intensive comprehensive rehabilitation.

Stroke often impairs upper extremity motor function, with recovery in the sub-acute phase being crucial for regaining independence. This study examines changes in isometric muscle strength, dexterity, and self-care independence during this period, and evaluates the effects of a comprehensive intensive rehabilitation (COMIRESTROKE). Individuals in sub-acute stroke recovery and age- and sex-matched controls were assessed for pre- and post-rehabilitation differences in primary outcomes (grip/pinch strength, Nine Hole Peg Test [NHPT], Action Research Arm Test [ARAT]). COMIRESTROKE's effects on primary and secondary outcomes (National Institute of Health Stroke Scale [NIHSS], Modified Rankin Scale [MRS], Functional Independence Measure [FIM]) were evaluated. Outcomes were analyzed for dominant and non-dominant limbs, both regardless of impairment and with a focus on impaired limbs. Fifty-two individuals with stroke (NIHSS 7.51 ± 5.71, age 70.25 ± 12.66 years, 21.36 ± 12.06 days post-stroke) and forty-six controls participated. At baseline, individuals with stroke showed significantly lower strength (dominant grip, key pinch, tip-tip pinch, p adj < 0.05), higher NHPT scores (p adj < 0.05), and lower ARAT scores (p adj < 0.001). COMIRESTROKE led to improvements in dominant key pinch, non-dominant tip-tip pinch, NHPT, and both dominant and non-dominant ARAT (p adj < 0.05). Notably, non-dominant key pinch improved significantly when considering only impaired hands. Pre- and post-test differences between groups were significant only for ARAT (both limbs), even after adjustment (p adj < 0.05). All secondary outcomes (NIHSS, MRS, FIM) showed significant improvement post-COMIRESTROKE (p adj < 0.001). Individuals with stroke exhibit reduced muscle strength and dexterity, impairing independence. However, comprehensive intensive rehabilitation significantly improves these functions. Data are available from the corresponding author upon request and are part of a sub-study of NCT05323916.

The effectiveness of vitamin D supplementation in patients with end-stage knee osteoarthritis: Study protocol for a double-blinded, randomized controlled trial.

Osteoarthritis (OA) knee is one of the most common chronic degenerative conditions that imposes clinical and economic burdens on individuals and societies worldwide. Previous studies showed vitamin D levels correlated positively with lean muscle mass and grip strength, implying that vitamin D supplementation may improve muscle health in knee OA subjects. This randomized controlled trial (RCT) aims to compare the effects of vitamin D supplementation on knee muscle strength, physical function, pain, and sarcopenia status in patients with end-stage knee OA. Patients and outcome assessors will be blinded to group allocation. Fifty-six end-stage knee OA patients with vitamin D insufficiency fulfilling our inclusion criteria will be invited to participate in this study. Patients will be randomly assigned to take vitamin D supplementation (4,000 IU capsule daily) or placebo for six months. Measurements will be taken at baseline, three and six-month after the commencement of the vitamin D supplement, and 6-month after the interventional period. The primary outcome includes the isometric quadriceps and hamstring muscle strength measured by a hand-held dynamometer. Secondary outcomes include pain, performance-based and self-reported physical function and sarcopenia status. The success of this study will provide scientific evidence of whether the relatively cheap and well-tolerated vitamin D supplement can improve quadriceps muscle strength, physical function, pain symptoms, and sarcopenia status of this increasingly large population for end-stage knee OA patients. The study has great clinical significance given Hong Kong's lengthy and growing waiting list for complete knee replacement procedures. Trial registration: The trial was registered on clinicaltrials.gov (NCT05981534) on 31st July 2023.

Effects of Resistance Training Volume on Physical Function, Lean Body Mass and Lower-Body Muscle Hypertrophy and Strength in Older Adults: A Systematic Review and Network Meta-analysis of 151 Randomised Trials.

The optimal prescription and precise recommendations of resistance training volume for older adults is unclear in the current literature. In addition, the interactions between resistance training volume and program duration as well as physical health status remain to be determined when assessing physical function, muscle size and hypertrophy and muscle strength adaptations in older adults. This study aimed to determine which resistance training volume is the most effective in improving physical function, lean body mass, lower-limb muscle hypertrophy and strength in older adults. Additionally, we examined whether effects were moderated by intervention duration (i.e. short term, < 20weeks; medium-to-long term, ≥ 20weeks) and physical health status (i.e. physically healthy, physically impaired, mixed physically healthy and physically impaired; PROSPERO identifier: CRD42023413209). CINAHL, Embase, LILACS, PubMed, Scielo, SPORTDiscus and Web of Science databases were searched up to April 2023. Eligible randomised trials examined the effects of supervised resistance training in older adults (i.e. ≥ 60years). Resistance training programs were categorised as low (LVRT), moderate (MVRT) and high volume (HVRT) on the basis of terciles of prescribed weekly resistance training volume (i.e. product of frequency, number of exercises and number of sets) for full- and lower-body training. The primary outcomes for this review were physical function measured by fast walking speed, timed up and go and 6-min walking tests; lean body mass and lower-body muscle hypertrophy; and lower-body muscle strength measured by knee extension and leg press one-repetition maximum (1-RM), isometric muscle strength and isokinetic torque. A random-effects network meta-analysis was undertaken to examine the effects of different resistance training volumes on the outcomes of interest. We included a total of 161 articles describing 151 trials (n = 6306). LVRT was the most effective for improving timed up and go [- 1.20 standardised mean difference (SMD), 95% confidence interval (95% CI): - 1.57 to - 0.82], 6-min walk test (1.03 SMD, 95% CI: 0.33-1.73), lean body mass (0.25 SMD, 95% CI: 0.10-0.40) and muscle hypertrophy (0.40 SMD, 95% CI: 0.25-0.54). Both MVRT and HVRT were the most effective for improving lower-limb strength, while only HVRT was effective in increasing fast walking speed (0.40 SMD, 95% CI: - 0.57 to 0.14). Regarding the moderators, our results were independent of program duration and mainly observed for healthy older adults, while evidence was limited for those who were physically impaired. A low resistance training volume can substantially improve healthy older adults' physical function and benefits lean mass and muscle size independently of program duration, while a higher volume seems to be necessary for achieving greater improvements in muscle strength. A low volume of resistance training should be recommended in future exercise guidelines, particularly for physically healthy older adults targeting healthy ageing.

Comprehensive assessment of heavy slow resistance training and high-dose therapeutic ultrasound in managing patellar tendinopathy, a randomized single-blind controlled trial

BackgroundPatellar tendinopathy (PT) is a common sport injury prone to recurrence. Heavy Slow Resistance Training (HSR) and High-Dose Therapeutic Ultrasound (TUS) are frequently used interventions for PT. However, the combined effectiveness of these therapies remains unclear. This study investigated the impact of combination therapy on functional outcomes in patients with PT.MethodsFifty-one college students aged 18–25, diagnosed with PT via musculoskeletal ultrasound, were randomly assigned to one of three groups (n = 17 per group): combined HSR and high-dose TUS, HSR training alone, or high-dose TUS alone. The eight-week intervention included assessments using the Victorian Institute of Sport Assessment-Patella (VISA-P), Visual Analogue Scale (VAS), Y-balance Test (YBT), Modified Thomas Test (MTT), Horizontal Jumping Distance, Maximum Isometric Muscle Strength Test, and musculoskeletal ultrasound for patellar tendon thickness and blood flow. Assessments were conducted at baseline and post-intervention, with a follow-up VISA-P assessment at week 16. This randomized, single-blind controlled trial was registered on ISRCTN11447397 (www.ISRCTN.com) on February 17, 2024 (retrospectively registered).ResultsAll groups demonstrated significant improvements in VISA-P scores at the end of the intervention compared to baseline (p < 0.01), with the combined group showing the greatest improvement (21 points). Follow-up at week 16 revealed continued improvement in VISA-P scores for the combined and HSR groups, while the TUS group showed a slight decrease (from 74 to 70). All groups displayed significantly reduced VAS scores post-intervention (p < 0.01) compared to baseline, indicating decreased pain. While no significant between-group differences were observed in pre-intervention VAS scores, post-intervention results revealed significant differences between the combined and HSR groups (p < 0.05), as well as between the combined and TUS groups (p < 0.01).ConclusionBoth exercise intervention and high-dose TUS appear effective in reducing pain and improving motor function in individuals with PT. However, the therapeutic effect of high-dose TUS alone seems limited compared to exercise intervention. The combined application of both methods yielded the most significant improvements in pain relief and motor function enhancement.

Maximum Isokinetic Eccentric Elbow Flexor Muscle Force Can Be Estimated Using Maximum Isometric Contraction Force.

Purpose It is difficult to measure maximal isokinetic eccentric (ECC) muscle strength in the sports field. This study aimed to investigate whether elbow isometric (ISO) flexion muscle strength or muscle thickness (MT) can be used to estimate elbow ECC flexion muscle strength. Material and methods Maximal muscle strength and muscle thickness (MT) were measured in the elbow flexor muscle group of 147 healthy adults (age: 21.3±0.8 years, height: 167.3±8.6 cm, body mass: 61.4±10.6 kg: 99 males and 48 females). Both isometric contraction (ISO) and eccentric contraction (ECC) of elbow flexion muscle strength were measured using an isokinetic dynamometer. The ultrasound measured MT at 50% of the distance from the upper arm to the lateral epicondyle. We performed the multiple regression analysis with elbow ECC flexion muscle strength as the dependent variable and gender, age, height, body mass, elbow ISO flexion muscle strength, and MT as the independent variables. Results Multiple regression analysis revealed a coefficient of determination R2 value of 0.89 and an adjusted R2 value of 0.89 (p<0.01). In addition, the independent variables elbow ISO flexor strength (p<0.01, standardized coefficient β=0.94; p<0.01, standardized coefficient β=0.89) and muscle thickness (p<0.05, standardized coefficient β=0.07) were identified as significantly associated factors. Conclusions The results suggest that it is possible to estimate elbow ECC flexion muscle strength using only elbow ISO flexion muscle strength and that ECC flexion muscle strength can be estimated more accurately by adding muscle thickness of the elbow flexor muscle group.

Effects of over 10 weeks of resistance training on muscle and bone mineral density in older people with sarcopenia over 70 years old: A systematic review and meta-analysis of randomized controlled trials

ObjectiveWe aimed to examine the effects of more than 10 weeks of resistance training (RT) on muscle structure, muscle function, and bone mineral density (BMD) in older people with sarcopenia over 70 years old MethodsPubMed, Web of Science, Embase, MEDLINE, Cochrane Library, and CINAHL databases were searched for randomized controlled trials. Standardized mean difference (MD) or standard mean difference (SMD) was used to pool the effect of the RT intervention ResultsThirteen studies with 2080 older adults with sarcopenia were included. Resistance exercise significantly affected handgrip strength (MD = 1.67 kg; P = 0.02) and isometric muscle strength (standard mean difference [SMD] = 0.53; P = 0.02). Significant differences in chair stand test (SMD = 0.40; P = 0.02) and skeletal muscle mass index (mean difference [MD] = 1.67 kg/m2; P = 0.0002) were found between the RT and control groups ConclusionMore than 10 weeks of RT has beneficial effects on muscle but no favorable effect on BMD in older people with sarcopenia over 70 years old.

Reliability of a Flight Helmet-Attached Force Gauge in Measuring Isometric Neck Muscle Strength

INTRODUCTION: Strong neck muscles may decrease the risk of flight-induced neck pain and possible disability among fast jet pilots. The purpose of this study was to examine the intra- and interrater reliability of a commercial force gauge attached to a pilot’s helmet for measuring isometric force production of the neck muscles. METHODS: A total of 41 subjects performed maximal isometric cervical flexion, extension, and lateral flexion in two measurement sessions for intrarater reliability, and 31 of these subjects participated in a third session for measuring interrater reliability. Delayed muscle soreness and neck pain were assessed using the Visual Analog Scale before and after each measurement session. The intraclass correlation coefficient (ICC) was used to compare values between the test and retest assessments. RESULTS: The overall interrater reliability was good (ICC 0.79–0.90), whereas the intrarater reliability varied from moderate to good (ICC 0.58–0.84). In both intra- and interrater reliability, the flexion test had good (ICC 0.84–0.89) reliability, while the lateral flexion test results had moderate to good (ICC 0.73–0.90) reliability. The extension test had the lowest reliability in both intra- (ICC 0.58) and interrater (ICC 0.79) tests. The average visual analog scale score (from 1–100 scale) prior to the second measurement session was 16 ± 18 in delayed muscle soreness and 0 ± 0 in neck pain. DISCUSSION: The present study demonstrated that the helmet-attached force gauge is a reliable, safe, and clinically applicable method to evaluate isometric neck strength in the flexion and lateral flexion directions. Honkanen T, Mattila V, Kinnunen O, Janhunen M, Sovelius R, Vaara JP, Kyröläinen H. Reliability of a flight helmet-attached force gauge in measuring isometric neck muscle strength. Aerosp Med Hum Perform. 2024; 95(10):788–793.

How Does Standing Anteroposterior Stability Limits Correlate to Foot/ankle Functions in Bilateral Spastic Cerebral Palsy?

To determine whether foot and ankle functions are correlated with the limits of stability (LoS) while standing in individuals with bilateral spastic cerebral palsy (BSCP). Eighteen people who could walk and with BSCP and 18 people without disability participated. Anteroposterior LoS was measured using a force platform. To quantify ankle and foot functions, spasticity, isometric muscle strength, passive range of motion, and plantar light touch-pressure sensation were assessed. In the BSCP group, anteroposterior LoS was significantly decreased, and anterior LoS reduction was correlated with decreases in plantar flexor and toe flexor strength and in sensitivity of the forefoot to light touch-pressure sensation, whereas the posterior LoS reduction was correlated with reduced dorsiflexor strength. The present findings suggest that improvement in these foot and ankle functions in BSCP may increase LoS while standing.

Free-Weight Resistance Training Enhances Core Muscle Strength but Does Not Translate to Improved Athletic Performance in Adolescent Canoe/Kayak Athletes.

While previous evidence has shown that using free weights for resistance training is a more practical approach to enhancing strength, there is a relatively low prevalence of free-weight resistance training among adolescent kayak/canoe athletes. Therefore, this study aims to assess the impact of free-weight resistance training on body composition and various performance factors among adolescent canoe/kayak athletes. Twenty-seven young sprint kayakers and canoeists (14 ± 1 years; 164 ± 7 cm; 56 ± 8 kg) completed this study. Following baseline assessments, athletes were randomly divided into two training groups: the free-weight resistance training group (FW) or the control group (C). The FW group underwent free-weight resistance training sessions twice weekly for 24 weeks. The C group maintained their regular bodyweight training sessions during the same timeframe. All participants performed both the pre- and post-training assessments for the following dependent variables: body composition, upper-body power, upper-body isometric muscle strength, isometric mid-thigh pull, core strength, countermovement jump, balance, anaerobic ability, and aerobic performance. After 24 weeks of training, the free-weight resistance training group exhibited a significant increase in body weight (from 56 ± 5 kg to 58 ± 4 kg, p < 0.05) and improvements in the number of straight leg raise repetitions (from 23 ± 6 to 26 ± 4, p < 0.05) compared to the control group. However, the two groups observed no significant differences between upper-body isometric muscle strength, power, balance, and anaerobic/aerobic performance. A 24-week training duration might be insufficient for novice participants in resistance training. Future research should consider incorporating an adaptation period or a learning phase for movements before training, thereby enhancing the efficacy of free-weight resistance training in increasing strength.

Fall assessment in healthy older adults: Approach using rambling-trembling decomposition method

BackgroundThis study explored useful indices of potential fall risk in healthy older adults based on comprehensive clinical and simple quantitative posturographic measurements. MethodsA total of 64 community-dwelling older adults aged ≥65 years were classified into fallers and non-fallers based on previous fall history. After excluding two participants due to missing data, 16 and 46 participants were included in the faller and non-faller groups, respectively. We conducted major clinical measurements, including timed up and go test, 10-m walk test, functional reach test, one-leg stand test, isometric muscle strength tests, open-close stepping test, and sit-to-stand test. For quantitative posturographic measurements, participants performed standing tasks with their eyes open and closed. In the standing tasks, the time series of the center of pressure in the anteroposterior and mediolateral directions were measured and decomposed into rambling and trembling components to evaluate postural control in detail, separately. The mean velocity and root mean square of the center of pressure, rambling, and trembling were calculated and compared between fallers and non-fallers. FindingsA significant fall-related difference was found only in the mean velocity of the rambling in the anteroposterior direction; fallers displayed greater values than non-fallers, especially while standing with their eyes closed. InterpretationThe clinical measures failed to distinguish differences in fall risk, whereas the rambling component in the anteroposterior direction could detect substantial differences. The mean velocity of the rambling component could be useful as a sensitive screening biomarker for potential fall risks in healthy older adults.

Suspension training improves bilateral isometric strength asymmetry of knee muscles in people with multiple sclerosis

IntroductionMost people with multiple sclerosis are diagnosed with bilateral strength asymmetry in the lower limbs. Strength asymmetry increases muscle metabolic cost, muscle fatigability, postural instability, gait disturbance, imbalance, and risk of falling, and negatively affects the quality of life in PwMS. So far, the effects of rehabilitation exercises on reducing the asymmetric index in this population has not been studied convincingly. The purpose of this study was to investigate the effect of suspension exercise on bilateral isometric strength asymmetry of knee muscles in patients with multiple sclerosis. Materials & methodsIn this randomized controlled trial, twenty-seven female patients were purposively selected as the statistical sample and randomly divided into the control (n = 13, age: 34.72 ± 5.01 years) and exercise (n = 14, age: 37.62 ± 4.58 years) groups. The control group received routine care while the exercise group received the suspension exercise protocol. Isometric muscle strength and bilateral asymmetry were measured at baseline and after 8 weeks. The Biodex isokinetic dynamometer was used to measure the maximal voluntary isometric contraction of the flexor and extensor muscles of the knee. The analysis of covariance was used to analyze the data. ResultsThe isometric strength of the knee extensor muscles in the weak leg at the angle of 20° and in both legs at the angle of 70° in the exercise group improved significantly. Furthermore, the strength of the knee flexor muscles in the exercise group was increased. The amount of bilateral strength asymmetry in the knee flexor and extensor muscles at the angle of 70° significantly decreased in the exercise group. Discussions & conclusionsThese data suggest that suspension training is a practical approach to manage bilateral asymmetry in knee flexor and extensor muscle strength in patients with an EDSS of less than four.

Effect of training in a sandy environment on foot morphology and function

BackgroundAthletes need to enhance their foot function to improve their performance and prevent injuries and disability. Although foot function is believed to be improved by stabilizing the body on an unstable surface (e.g., a sandy beach), there have been no relevant studies to our knowledge. Here, we identified the differences in foot and balance functions between beach volleyball and volleyball players and investigated the effects of sandy surface training. MethodsWe included six male beach volleyball players (BVB group) and six male volleyball players (VB group). The following six parameters were measured and compared between the groups: foot morphology, plantar surface perception, isometric ankle muscle strength, toe grip strength, static balance, and dynamic balance. ResultsThe BVB group had significantly higher values in sensation perception, isometric ankle dorsiflexion muscle strength, and toe grip strength in the standing posture, with significant intrinsic foot muscle dominance, compared to the VB group. ConclusionPlaying barefoot increases the amount of tactile information received from the surface of the sole, which may lead to enhanced sensory perception by the foot. In addition, owing to the unstable sandy surface, the intrinsic muscles of the foot and lower leg may strengthen to maintain balance; therefore, training on a sandy surface may lead to improved foot and balance functions.

Changes in Physiopathological Markers in Myotonic Dystrophy Type 1 Skeletal Muscle: A 3-Year Follow-up Study.

Myotonic dystrophy type 1 (DM1) is a slowly progressive disease caused by abnormal CTG repetitions on the dystrophia myotonica protein kinase (DMPK) gene. Long mRNA from CTG repetitions stabilizes in nuclear foci and sequester muscleblind-like splicing regulator 1 (MBNL1). Cardinal signs of DM1 include muscle wasting and weakness. The impacts of DM1 progression on skeletal muscle are under-researched. Identifying physiopathological markers related to maximal strength loss over time in DM1. Twenty-two individuals with DM1 participated in two maximal isometric muscle strength (MIMS) evaluations of their knee extensors and two vastus lateralis muscle biopsies, 3 years apart. Muscle fiber typing, size (including minimal Feret's diameter [MFD] and atrophy/hypertrophy factors [AF/HF]), and nuclear foci and MBNL1 colocalization (foci/MBNL1+) were evaluated. Immunoblotting was used to measure glycogen synthase kinase-3 beta (GSK3β), p62, LC3BI, LC3BII, and oxidative phosphorylation proteins. There are significant correlations between the fold changes of MIMS with type 1 fiber MFD (ρ= 0.483) and AF (ρ= -0.514). Regression analysis shows that baseline percentage of foci/MBNL1+ nuclei and strength training explain 44.1% of foci/MBNL1+ nuclei percentage variation over time. There are fair to excellent correlations between the fold changes of MIMS and GSK3β (ρ= 0.327), p62 (ρ= 0.473), LC3BI (ρ= 0.518), LC3BII (ρ= -0.391) and LC3BII/LC3BI (ρ= -0.773). Type 1 MFD decrease and AF increase are correlated with MIMS loss. There seems to be a plateau effect in foci/MBNL1+ nuclei accumulation and strength training helps decrease this accumulation. Autophagy marker LC3BII/LC3BI ratio has a good biomarker potential of MIMS loss, but more investigations are needed.

Literature review of specific techniques in catching and throwing in infield defense in baseball - retrospective article

&lt;p&gt;目的：內野手可以是整個棒球守備的核心，棒球守備各階段全身上下的協調，有許多值得探討的專項技巧。方法：本研究使用Google scholar，以Baseball infielder、內野、野球守備、內野捕球、守備ゴロ等關鍵字，搜尋台灣、日本、美國三國關於棒球內野守備專項技巧的文獻做歸納，以不同角度探討內野守備的專項技巧：一、內野守備接球，二、內野守備傳球，三、守備的分期與各分期之動作控制。結果：本篇回顧性論文發現，一、移動腳步到好接球的彈跳點是良好守備的關鍵。二、減少軸心腳在接球位置上的變化和較為前面的接球點，對於接球的穩定性至關重要，甚至會影響到後續傳球的動能。三、精簡接傳的動作相較於增加傳球球速可能可以更能有效減少整體守備時間。四、優秀選手在接球的過程中會儘早讓軸心腳著地，並前期和中期將重心保留在軸心腳。五、內野手傳球在前導腳接觸時，軀幹向後扭轉和肘部伸展角度都會比投手小。結論：無論是接球前腳步移動的節奏和精確性，還是接球時的接球點和接短彈跳的能力，甚至是軀幹和骨盆前傾的時機點，對於內野守備過程都產生一定的影響。建議在日常練習時，就能將接短彈跳、腳步移動，納入訓練課表中，並且在動作過程中，加以檢視軀幹的姿勢，方能在比賽時擁有良好的守備表現。&lt;/p&gt; &lt;p&gt;&amp;nbsp;&lt;/p&gt;&lt;p&gt;The standing throw with run-up is the best approach to evaluate the performance of energy transfer and the efficiency of throwing motions for handball players. Purpose: This research aims at analyzing the usage of the standing throw with run-up among the handball players in Taiwan. The roles of body kinematics, strength of core muscles and standing balance of the drive leg played in the standing throw with run-up are also discussed. Methods: Nine Division I handball players from college went through a series of tests. The motions and the speed of the handball throwing were detected by a 3D electromagnetic motion analysis system and a sports radar gun, respectively. The maximum isometric muscle strength of trunks and hips were measured by a torque sensor and a home-made device of strength measurement. The standing balance of the drive leg was measured by a force plate with a mat. Results: The maximal shoulder external rotation angle in the arm cocking phase, the maximal trunk rotation velocity in the arm acceleration phase and the maximal shoulder horizontal adduction velocity showed moderate positive relationships with the ball velocity. The strength of back muscles had a moderate negative relationship with the ball velocity. The correlation between the balance ability of the drive leg and the ball velocity was not observed. Conclusion: The importance of proximal segments to the standing throw with run-up is analyzed by kinematical analysis. It is suggested that the energy of handball throwing is generated by the upper extremities or other limb segments in the processes of the standing throw with run-up. Our findings can serve as a helpful reference for both coaches and players.&lt;/p&gt; &lt;p&gt;&amp;nbsp;&lt;/p&gt;