A follow-up study on respiratory outcomes, quality of life and performance perception of SARS-CoV-2 primary and reinfection in elite athletes: A 9-month prospective study.

The prolonged consequences of SARS-CoV-2 on young elite athletes recovering from primary and reinfection are unclear. This study aimed to assess inspiratory/expiratory muscle strength and respiratory function at the time of spontaneous recovery at 3, 6, and 9 months after SARS-CoV-2 primary and reinfection in elite athletes. The study enrolled 25 elite male judoists, including 11 primary infection cases, five reinfection cases, and nine controls from the Türkiye Olympic Preparation Center. Inspiratory/expiratory muscle strength and respiratory function were measured, including maximal inspiratory pressure (MIP), maximal expiratory pressure (MEP), forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), FEV1/FVC, and peak expiratory flow (PEF) before and up to 9 months after SARS-CoV-2 infection in the early pre-competition preparation phases. The most common symptoms reported by reinfection cases were fatigue (80%), dyspnea (60%), and muscle/joint pain (60%), while primary infection cases reported fatigue (73%), muscle/joint pain (45%), and headache (45%). MIP decreased by -14% and MEP decreased by -13% following the SARS-CoV-2 infection in reinfection cases. Likewise, FEV1 and FVC decreased by -5% and -8%, respectively; consequently, FEV1/FVC increased by 3%. Inspiratory/expiratory muscle strength and respiratory function improved rapidly after 9 months of SARS-CoV-2 infection in primary cases, whereas dysfunction persisted in reinfection cases. PEF was unaffected throughout the 9-month follow-up period. Reinfection may lead to further alterations in respiratory system relative to the primary infection, with a suspected restrictive pattern that remains dysfunctional in the third month; however, it improves significantly during a 9-month follow-up period.

Optimizing exercise prescription during breast cancer rehabilitation in women: Analysis of the load-velocity relationship in the box squat exercise.

The aims of this study were to assess (i) the load-velocity relationship during the box squat exercise in women survivors of breast cancer, (ii) which velocity variable (mean velocity [MV], mean propulsive velocity [MPV], or peak velocity [PV]) shows stronger relationship with the relative load (%1RM), and (iii) which regression model (linear [LA] or polynomic [PA]) provides a greater fit for predicting the velocities associated with each %1RM. Nineteen women survivors of breast cancer (age: 53.2 ± 6.9 years, weight: 70.9 ± 13.1 kg, and height: 163.5 ± 7.4 cm) completed an incremental load test up to one-repetition maximum in the box squat exercise. The MV, MPV, and the PV were measured during the concentric phase of each repetition with a linear velocity transducer. These measurements were analyzed by regression models using LA and PA. Strong correlations of MV with %1RM (R2 = 0.903/0.904; the standard error of the estimate (SEE) = 0.05 m.s-1 by LA/PA) and MPV (R2 = 0.900; SEE = 0.06 m.s-1 by LA and PA) were observed. In contrast, PV showed a weaker association with %1RM (R2 = 0.704; SEE = 0.15 m.s-1 by LA and PA). The MV and MPV of 1RM was 0.22 ± 0.04 m·s-1, whereas the PV at 1RM was 0.63 ± 0.18 m.s-1. These findings suggest that the use of MV to prescribe relative loads during resistance training, as well as LA and PA regression models, accurately predicted velocities for each %1RM. Assessing and prescribing resistance exercises during breast cancer rehabilitation can be facilitated through the monitoring of movement velocity.

Effects of weight-bearing dance aerobics on lower limb muscle morphology, strength and functional fitness in older women.

Objective: To investigate the effects of 12-week weight-bearing dance aerobics (WBDA) on muscle morphology, strength and functional fitness in older women. Methods: This controlled study recruited 37 female participants (66.31y ± 3.83) and divided them into intervention and control groups according to willingness. The intervention group received 90-min WBDA thrice a week for 12 weeks, while the control group maintained normal activities. The groups were then compared by measuring muscle thickness, fiber length and pennation angle by ultrasound, muscle strength using an isokinetic multi-joint module and functional fitness, such as 2-min step test, 30-s chair stand, chair sit-and-reach, TUG and single-legged closed-eyed standing test. The morphology, strength, and functional fitness were compared using ANCOVA or Mann-Whitney U test to study the effects of 12 weeks WBDA. Results: Among all recruited participants, 33 completed all tests. After 12 weeks, the thickness of the vastus intermedius (F = 17.85, P < 0.01) and quadriceps (F = 15.62, P < 0.01) was significantly increased in the intervention group compared to the control group, along with a significant increase in the torque/weight of the knee flexor muscles (F = 4.47, P = 0.04). Similarly, the intervention group revealed a significant improvement in the single-legged closed-eyed standing test (z = -2.16, P = 0.03) compared to the control group. Conclusion: The study concluded that compared to the non-exercising control group, 12-week WBDA was shown to thicken vastus intermedius, increase muscle strength, and improve physical function in older women. In addition, this study provides a reference exercise program for older women.

Malnutrition contribution to the functional status and health related quality of life after COVID-19, a correlational follow-up study.

To assess malnutrition contribution to the functional status and health related quality of life after hospitalization due to COVID-19 pneumonia, 66 selected adults referred for physical rehabilitation accepted to participate in the study; none of them required oxygen supply or had history of lung/musculoskeletal/neurological/immune/rheumatic disease or trauma, or contraindication for respiratory-function tests. At three evaluations, with 3 months in-between, assessments included: self-report of functional status, the St. George's Respiratory Questionnaire, spirometry, the 6-min-walk-test, the MRC-scale, the 30-s sit-to-stand-test, the timed-up-and-go-test, nutritional status, and ultrasound imaging (vastus medialis and diaphragm). At referral, patients had nutritional deficits with protein deficiency, which gradually improved; while muscle thickness (of both vastus medialis and diaphragm) increased, along with muscle strength and mobility (ANOVA, p < 0.05). Contrarywise, the distance covered during the 6-min-walk-test decreased (ANOVA, p < 0.05), with a negative influence from excess body mass. During rehabilitation, health-related quality of life and functional status improved, with negative influence from a history of tobacco use and referral delay, respectively. After hospitalization due to COVID-19, early diagnosis of both protein deficiency and decrease of skeletal muscle thickness could be relevant for rehabilitation, while pondering the negative impact of excess body mass on submaximal exercise performance.

Effects of high-definition transcranial direct current stimulation combined with inspiratory muscle training for treating respiratory sequelae of long COVID: A case series.

INTRODUCTION: Long COVID occurs when numerous symptoms begin 3 weeks after acute infection and last for 12 months or more. High-definition transcranial direct current stimulation (HD-tDCS) has been tested in patients with COVID-19; however, previous studies did not investigate the HD-tDCS use combined with inspiratory muscle training (IMT) for respiratory sequelae of long COVID. CASE PRESENTATION: Six individuals (four women and two men) aged between 29 and 71 years and presenting with respiratory sequelae of long COVID were included. They were submitted to an intervention that comprised HD-tDCS combined with IMT twice a week for 5 weeks. Lung function and respiratory muscle assessments were performed at baseline and after 5 weeks of intervention. IMPLICATIONS ON PHYSIOTHERAPY PRACTICE: HD-tDCS may enhance the IMT effects by increasing respiratory muscle strength, efficiency, and lung function of individuals with long COVID.

Effect of rest duration between sets on fatigue and recovery after short intense plyometric exercise.

Plyometric training is characterized by high-intensity exercise which is performed in short term efforts divided into sets. The purpose of the present study was twofold: first, to investigate the effects of three distinct plyometric exercise protocols, each with varying work-to-rest ratios, on muscle fatigue and recovery using an incline-plane training machine; and second, to assess the relationship between changes in lower limb muscle strength and power and the biochemical response to the three exercise variants employed. Forty-five adult males were randomly divided into 3 groups (n = 15) performing an exercise of 60 rebounds on an incline-plane training machine. The G0 group performed continuous exercise, while the G45 and G90 groups completed 4 sets of 15 repetitions, each set lasting 45 s with 45 s rest in G45 (work-to-rest ratio of 1:1) and 90 s rest in G90 (1:2 ratio). Changes in muscle torques of knee extensors and flexors, as well as blood lactate (LA) and ammonia levels, were assessed before and every 5 min for 30 min after completing the workout. The results showed significantly higher (p < 0.001) average power across all jumps generated during intermittent compared to continuous exercise. The greatest decrease in knee extensor strength immediately post-exercise was recorded in group G0 and the least in G90. The post-exercise time course of LA changes followed a similar pattern in all groups, while the longer the interval between sets, the faster LA returned to baseline. Intermittent exercise had a more favourable effect on muscle energy metabolism and recovery than continuous exercise, and the work-to-rest ratio of 1:2 in plyometric exercises was sufficient rest time to allow the continuation of exercise in subsequent sets at similar intensity.

Which intervention is optimal to control blood glucose and improve physical performance in the elderly living with type 2 diabetes mellitus? A network meta-analysis.

BACKGROUND AND OBJECTIVES: This study aimed to find the optimal intervention available to both control blood glucose and improve physical function in the geriatric population with T2DM. METHODS AND STUDY DESIGN: A systemic review and network meta-analysis (NMA) was conducted to assess and rank the comparative efficacy of different interventions on glycosylated hemoglobin A1c (HbAc1), fasting blood glucose (FBG), muscle mass, grip strength, gait speed, lower body muscle strength, and dynamic balance. A total of eight databases were searched for eligible randomized controlled trials (RCTs) that the elderly aged more than 60 years or with mean age ≥ 55 years, the minimal duration of the RCT intervention was 6 weeks, and those lacking data about glycemic level and at least one indicator of physical performance were excluded. The Cochrane risk of bias tool was used to assess the bias of each study included. Bayesian NMA was performed as the main results, the Bayesian meta regression and the frequentist NMA as sensitivity analysis. RESULTS: Of the 2266 literature retrieved, 27 RCTs with a total of 2289 older adults were included. Health management provided by health workers exerts beneficial effects that is superior to other interventions at achieving glycemic control, but less marked improvement in physical performance. Exercise combined with cognitive training showed more pronounced improvement in muscle strength, gait speed, and dynamic balance, but ranked behind in decreasing the HbAc1 and FBG. CONCLUSIONS: Personalized health management combined with physical and cognitive training might be the optimal intervention to both accomplish glycemic control and improvement of physical performance. Further RCTs are needed to validate and assess the confidence of our results from this NMA.

Peri-ankle muscles architecture and performance changes in patients with chronic ankle instability: A retrospective cross-sectional study.

This study aimed to identify changes in the architecture and performance of the peri-ankle muscles in patients with chronic ankle instability (CAI) and investigate the relationship between them. In total, 17 subjects were evaluated retrospectively. Each subject underwent anthropometric and isokinetic test, and peroneus longus (PL) and brevis (PB), medial gastrocnemius (MGCM), and tibialis anterior (TA) ultrasound imaging were performed at rest and maximum voluntary contraction (MVC) conditions. Regarding muscle architectural variables, the pennation angle (PA) of the MGCM at rest and the PA of the TA, MGCM, and PL in MVC were significantly reduced on the injured side compared to the intact side. There were no significant differences in muscle thickness of PL, PB, MGCM, and TA observed between intact and injured side during both rest and MVC. Regarding muscle performance parameters, significant decreased were observed in the muscle strength for both limbs in all four directions under the two different conditions. A secondary finding was that the relative PA ratio of the TA showed moderate correlation with the relative dorsiflexion ratio at 30°/s. These findings can provide opportunities to better understand how injuries in patients with CAI may be related to changes in ankle and foot function.

Examining body mass index and health-related fitness marker progression of incarcerated minority youth engaged in a sport-leadership program.

PURPOSE: The purpose of this study was to examine the impact of a sport-leadership program on minority incarcerated young adults' health-related fitness markers. DESIGN/METHODOLOGY/APPROACH: This study occurred at an all-male juvenile detention center. A total of 41 participants in this study were obtained from a sample of 103 incarcerated young adults. Data collection entailed body mass index (BMI) evaluation, cardiovascular endurance tests and 1-min pushups and situps at two different time periods (before and after three months). A 2 × 2 mixed factorial analysis of variances was used to test for differences among the within subjects' factors (time [pre × post]) and between subjects' factors (groups [flex × control]) for the above-mentioned dependent variables. FINDINGS: Over the course of three consecutive months of engagement, preliminary indications demonstrated participants had a slight reduction in BMI and significant increases in cardiovascular endurance and muscle strength. Contrarily, during this same time period, non-participating young adults exhibited significant increases in BMI and decreases in cardiovascular endurance and muscle strength. ORIGINALITY/VALUE: Integration of sport-leadership programs is generally not free but can be a low-cost alternative for combatting many issues surrounding physical activity, weight gain and recreational time for those incarcerated.

Estimates of functional muscle strength from a novel progressive lateral step-up test are feasible, reliable, and related to physical activity in children with cerebral palsy.

OBJECTIVE: To determine if estimates of functional muscle strength from a novel progressive lateral-step-up test (LSUT) are feasible, reliable, and related to physical activity in children with cerebral palsy (CP). DESIGN: Cross-sectional; test-retest reliability Subjects/Patients: Children with CP and typically developing control children (n = 45/group). METHODS: An LSUT with 10, 15, and 20 cm step heights was completed. It was repeated 4 weeks later in 20 children with CP. A composite score of LSUT was calculated based on the step height and number of repetitions completed. Physical activity was assessed using monitors worn on the ankle and hip. RESULTS: Only 4 (13%) of the children with CP were unable to complete a lateral step-up repetition without assistance. All children were able to complete at least 1 repetition with assistance, though more than twice as many children with CP required assistance at 15 and 20 cm step heights than at the 10 cm step height (p < 0.01). Children with CP had 59 to 63% lower LSUT performance, 37% lower physical activity assessed at the ankle, and 22% lower physical activity assessed at the hip than controls (all p < 0.01). The intra-class correlation coefficient ranged from 0.91 to 0.96 for LSUT performance at the different step heights and was 0.97 for the composite score. All LSUT performance measures were positively related to ankle physical activity in children with CP (r range = 0.43 to 0.47, all p < 0.01). Only performance at 20 cm and the composite score were positively related to hip physical activity (r = 0.33 and 0.31, respectively, both p < 0.05). The relationship between the LSUT performance and physical activity at both the ankle and hip increased when age and sex were statistically controlled (model r range = 0.55 to 0.60, all p < 0.001). CONCLUSION: Estimates of functional muscle strength from a novel progressive LSUT are feasible, reliable, and positively related to physical activity in children with CP.

Using Resistance-Band Tests to Evaluate Trunk Muscle Strength in Chronic Low Back Pain: A Test-Retest Reliability Study.

Exercise is a front-line intervention to increase functional capacity and reduce pain and disability in people with low strength levels or disorders. However, there is a lack of validated field-based tests to check the initial status and, more importantly, to control the process and make tailored adjustments in load, intensity, and recovery. We aimed to determine the test-retest reliability of a submaximal, resistance-band test to evaluate the strength of the trunk stability muscles using a portable force sensor in middle-aged adults (48 ± 13 years) with medically diagnosed chronic low back pain and healthy peers (n = 35). Participants completed two submaximal progressive tests of two resistance-band exercises (unilateral row and Pallof press), consisting of 5 s maintained contraction, progressively increasing the load. The test stopped when deviation from the initial position by compensation movements occurred. Trunk muscle strength (CORE muscles) was monitored in real time using a portable force sensor (strain gauge). Results revealed that both tests were highly reliable (intra-class correlation [ICC] > 0.901) and presented low errors and coefficients of variation (CV) in both groups. In particular, people with low back pain had errors of 14-19 N (CV = 9-12%) in the unilateral row test and 13-19 N (CV = 8-12%) in the Pallof press. No discomfort or pain was reported during or after the tests. These two easy-to-use and technology-based tests result in a reliable and objective screening tool to evaluate the strength and trunk stability in middle-aged adults with chronic low back pain, considering an error of measurement < 20 N. This contribution may have an impact on improving the individualization and control of rehabilitation or physical training in people with lumbar injuries or disorders.

Effect of Sampling Rate, Filtering, and Torque Onset Detection on Quadriceps Rate of Torque Development and Torque Steadiness.

Quadriceps rate of torque development (RTD) and torque steadiness are valuable metrics for assessing explosive strength and the ability to control force over a sustained period of time, which can inform clinical assessments of knee function. Despite their widespread use, there is a significant gap in standardized methodology for measuring these metrics, which limits their utility in comparing outcomes across different studies and populations. To address these gaps, we evaluated the influence of sampling rates, signal filtering, and torque onset detection on RTD and torque steadiness. Twenty-seven participants with a history of a primary anterior cruciate ligament reconstruction (N = 27 (11 male/16 female), age = 23 ± 8 years, body mass index = 26 ± 4 kg/m2) and thirty-two control participants (N = 32 (13 male/19 female), age = 23 ± 7 years, body mass index = 23 ± 3 kg/m2) underwent isometric quadriceps strength testing, with data collected at 2222 Hz on an isokinetic dynamometer. The torque-time signal was downsampled to approximately 100 and 1000 Hz and processed using a low-pass, zero-lag Butterworth filter with a range of cutoff frequencies spanning 10-200 Hz. The thresholds used to detect torque onset were defined as 0.1 Nm, 1 Nm, and 5 Nm. RTD between 0 and 100 ms, 0 and 200 ms, and 40-160 ms was computed, as well as absolute and relative torque steadiness. Relative differences were computed by comparing all outcomes to the "gold standard" values computed, with a sampling rate of 2222 Hz, a cutoff frequency in the low-pass filter of 150 Hz, and torque onset of 1 Nm, and compared utilizing linear mixed models. While all combinations of signal collection and processing parameters reached statistical significance (p < 0.05), these differences were consistent between injured and control limbs. Additionally, clinically relevant differences (+/-10%) were primarily observed through torque onset detection methods and primarily affected RTD between 0 and 100 ms. Although measurements of RTD and torque steadiness were generally robust against diverse signal collection and processing parameters, the selection of torque onset should be carefully considered, especially in early RTD assessments that have shorter time epochs.

Identifying fine motor difficulties in children with acute lymphoblastic leukemia: a scoping review.

PURPOSE: Survival rates for children diagnosed with acute lymphoblastic leukemia (ALL) have increased significantly over recent decades, and thus attention shifted toward understanding the adverse effects of cancer treatment. Chemotherapy has side effects that could affect muscle state and diminish motor performance. This scoping review was conducted to map the breadth of evidence for different tools used in fine motor skills assessment, the extent of upper extremity strength, and fine motor performance, highlighting the potential risk factors that may influence these skills. METHODS: In March 2023, full-text studies that examined fine motor performance and/or upper extremity strength were identified via searches in PubMed, Science Direct, Scopus, Web of Science, and PEDro databases. The titles and abstracts of selected studies were screened according to the inclusion and exclusion criteria. RESULTS: The search yielded initial 418 citations and 26 peer-reviewed articles were finally included in the review. Considerable heterogeneity was observed regarding the methods of evaluating fine motor skills. The results of this review indicate that children and adolescents with ALL experienced fine motor limitations and upper extremity weakness either during or after cessation of treatment. CONCLUSION: This scoping review presents a broad overview of the literature addressing fine motor difficulties in the pediatric population with ALL. Results accentuate the need to incorporate strengthening and occupational therapy training to preserve muscle strength and minimize future fine motor problems along the course of chemotherapeutic treatment. Little evidence was reported regarding the risk factors that may impair muscle strength and motor performance.

Meta-analysis of the therapeutic effect of electrical stimulation combined with pelvic floor muscle exercise on female pelvic floor dysfunction.

OBJECTIVES: To systematically evaluate the therapeutic effect of electrical stimulation combined with pelvic floor muscle exercise on female pelvic floor dysfunction (PFD). METHODS: Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) was applied. A computer-based retrieval was performed in the databases of PubMed, Web of Science, Embase, and Cochrane Library from database establishment to September 15, 2023, to identify randomized controlled trials on electrical stimulation combined with pelvic floor muscle function exercise on female PFD. Literature screening, data extraction, and quality evaluation were performed independently by two researchers, and meta-analysis was performed using the statistical software Stata15.0. RESULTS: 1. In total, 12 randomized controlled trials were included, involving 721 female patients. The overall quality of methodologies employed in the included studies was relatively high. 2. Meta-analysis results showed that electrical stimulation combined with pelvic floor muscle exercise could effectively mitigate the severity of female PFD (SMD = -1.01, 95% CI - 1.78, - 0.25, P < 0.05). 3. This combination treatment demonstrated a significant positive effect on the improvement of pelvic floor muscle strength in female patients (P < 0.05); however, it had no significant effect on the improvement in quality of life (P > 0.05). CONCLUSIONS: Compared with pelvic floor muscle exercise alone, electrical stimulation combined with pelvic floor muscle exercise could effectively mitigate the severity of female PFD. It had a notable positive impact on enhancing pelvic floor muscle strength in female patients, although it did not significantly improve quality of life. Future high-quality studies are warranted.

Influence of biceps-triceps ratio on golf swing performance.

OBJECTIVE: This study examines how maintaining a straight leading arm affects the muscle strength balance between the biceps and triceps in golfers and its influence on golf performance. METHODS: We recruited 20 male participants aged 18-45, including 10 golfers and 10 non-golfers. The participants' average age was 25.6±6.2 years, height 1.8±0.07 m, and weight 75.6±10.2 kg. We measured isometric and isokinetic muscle strength using the Primus RS Dynamometer (BTE Technologies, Hanover, MD, USA) and assessed golf swing performance with the Optishot 2 Golf Simulator (Optishot, Brighton, MI, USA). RESULTS: Golfers exhibited significantly greater triceps strength (P = 0.02) and a lower biceps-to-triceps strength ratio (P = 0.002) than non-golfers. Low-handicap golfers showed more centered and consistent ball impacts compared to mid-handicap golfers. There were no significant differences in swing path and face angles between low- and mid-handicap golfers. Muscle strength and the biceps-to-triceps strength ratio correlated with driving distance, as well as the frequencies of specific swing paths, face angles, and ball impact points, highlighting the complex interplay between muscle balance and swing performance. CONCLUSION: Greater triceps strength and a lower biceps-to-triceps strength ratio are key for maintaining a straight leading arm, especially in skilled golfers. While increased muscle strength tends to enhance driving distance, it does not necessarily improve accuracy. Consistent ball impact points may indicate higher skill levels. Future research should involve a larger, more diverse participant pool to validate these findings and further explore the complex nature of golf swing performance.

The prerequisites and clinical outcomes of ipsilateral C7 nerve root transfer to the upper trunk for adult C5-C6 brachial plexus injuries.

PURPOSE: Although ipsilateral C7 nerve transfer is used for the treatment of C5-C6 brachial plexus injuries, accurately evaluating the functional quality of the donor nerve (ipsilateral C7 nerve root) is difficult, especially when the C7 nerve root is slightly injured. The purpose of this study was to determine the indicators to evaluate the quality of the ipsilateral C7 nerve and assess the clinical outcomes of this procedure. METHODS: This study employed the following three indicators to assess the quality of the ipsilateral C7 nerve: (1) the muscle strength and electrophysiological status of the latissimus dorsi, triceps brachii, and extensor digitorum communis; (2) the sensibility of the radial three digits, especially the index finger; and (3) the intraoperative appearance, feel and electrophysiological status of the ipsilateral C7 nerve root. Transfer of the ipsilateral C7 nerve root to the upper trunk was implemented only when the following three tests were conducted, the criteria were met, and the clinical outcomes were assessed in eight patients with C5-C6 brachial plexus injuries. RESULTS: Patients were followed-up for an average of 90 ± 42 months. At the final follow-up, all eight patients achieved recovery of elbow flexion, with five and three patients scoring M4 and M3, respectively, according to the Medical Research Council scoring. The shoulder abduction range of motor recovery averaged 86 ± 47° (range, 30°-170°), whereas the shoulder external rotation averaged 51 ± 26° (range, 15°-90°). CONCLUSION: Ipsilateral C7 nerve transfer is a reliable and effective option for the functional reconstruction of the shoulder and elbow after C5-C6 brachial plexus injuries when the three prerequisites are met.

Early Predictors of Recovery From Nonoperatively Treated Achilles Tendon Rupture: 1 Year Follow-Up Study.

PURPOSE: To investigate early structural and mechanical predictors of plantarflexor muscle strength and the magnitude of Achilles tendon (AT) nonuniform displacement at 6 and 12 months after AT rupture. METHODS: Thirty-five participants (28 males and 7 females; mean ± SD age 41.7 ± 11.1 years) were assessed for isometric plantarflexion maximal voluntary contraction (MVC) and AT nonuniformity at 6 and 12 months after rupture. Structural and mechanical AT and plantarflexor muscle properties were measured at 2 months. Limb asymmetry index (LSI) was calculated for all variables. Multiple linear regression was used with the 6 and 12 month MVC LSI and 12 month AT nonuniformity LSI as dependent variables and AT and plantarflexor muscle properties at 2 months as independent variables. The level of pre- and post-injury sports participation was inquired using Tegner score at 2 and 12 months (scale 0-10, 10 = best possible score). Subjective perception of recovery was assessed with Achilles tendon total rupture score (ATRS) at 12 months (scale 0-100, 100=best possible score). RESULTS: Achilles tendon resting angle (ATRA) symmetry at 2 months predicted MVC symmetry at 6 and 12 months after rupture (ß = 2.530, 95% CI 1.041-4.018, adjusted R2 = 0.416, p = 0.002; ß = 1.659, 95% CI 0.330-2.988, adjusted R2 = 0.418, p = 0.016, respectively). At 12 months, participants had recovered their pre-injury level of sports participation (Tegner 6 ± 2 points). The median (IQR) ATRS score was 92 (7) points at 12 months. CONCLUSION: Greater asymmetry of ATRA in the early recovery phase may be a predictor of plantarflexor muscle strength deficits up to 1 year after rupture. TRIAL REGISTRATION: This research is a part of "nonoperative treatment of Achilles tendon rupture in Central Finland: a prospective cohort study" that has been registered in ClinicalTrials.gov (NCT03704532).

Differential training benefits and motor unit remodeling in wrist force precision tasks following high and low load blood flow restriction exercises under volume-matched conditions.

BACKGROUND: Blood flow restriction (BFR) resistance training has demonstrated efficacy in promoting strength gains beneficial for rehabilitation. Yet, the distinct functional advantages of BFR strength training using high-load and low-load protocols remain unclear. This study explored the behavioral and neurophysiological mechanisms that explain the differing effects after volume-matched high-load and low-load BFR training. METHODS: Twenty-eight healthy participants were randomly assigned to the high-load blood flow restriction (BFR-HL, n = 14) and low-load blood flow restriction (BFR-LL, n = 14) groups. They underwent 3 weeks of BFR training for isometric wrist extension at intensities of 25% or 75% of maximal voluntary contraction (MVC) with matched training volume. Pre- and post-tests included MVC and trapezoidal force-tracking tests (0-75%-0% MVC) with multi-channel surface electromyography (EMG) from the extensor digitorum. RESULTS: The BFR-HL group exhibited a greater strength gain than that of the BFR-LL group after training (BFR_HL: 26.96 ± 16.33% vs. BFR_LL: 11.16 ± 15.34%)(p = 0.020). However, only the BFR-LL group showed improvement in force steadiness for tracking performance in the post-test (p = 0.004), indicated by a smaller normalized change in force fluctuations compared to the BFR-HL group (p = 0.048). After training, the BFR-HL group activated motor units (MUs) with higher recruitment thresholds (p < 0.001) and longer inter-spike intervals (p = 0.002), contrary to the BFR-LL group, who activated MUs with lower recruitment thresholds (p < 0.001) and shorter inter-spike intervals (p < 0.001) during force-tracking. The discharge variability (p < 0.003) and common drive index (p < 0.002) of MUs were consistently reduced with training for the two groups. CONCLUSIONS: BFR-HL training led to greater strength gains, while BFR-LL training better improved force precision control due to activation of MUs with lower recruitment thresholds and higher discharge rates.

Efficacy of Pea Protein Supplementation in Combination with a Resistance Training Program on Muscle Performance in a Sedentary Adult Population: A Randomized, Comparator-Controlled, Parallel Clinical Trial.

Animal-sourced whey protein (WPr) is the most popular protein supplement among consumers and has been shown to improve muscle mass and strength. However, due to allergies, dietary restrictions/personal choices, and growing demand, alternative protein sources are warranted. Sedentary adults were randomized to pea protein (PPr) or WPr in combination with a weekly resistance training program for 84 days. Changes in whole-body muscle strength (WBMS) including handgrip, lower body, and upper body strength, body composition, and product perception were assessed. The safety outcomes included adverse events, vital signs, clinical chemistry, and hematology. There were no significant differences in the change in WBMS, muscle mass, or product perception and likability scores between the PPr and WPr groups. The participants supplemented with PPr had a 16.1% improvement in WBMS following 84 days of supplementation (p = 0.01), while those taking WPr had an improvement of 11.1% (p = 0.06). Both study products were safe and well-tolerated in the enrolled population. Eighty-four days of PPr supplementation resulted in improvements in strength and muscle mass comparable to WPr when combined with a resistance training program in a population of healthy sedentary adults. PPr may be considered as a viable alternative to animal-sourced WPr without sacrificing muscular gains and product enjoyment.

Aerobic high-intensity interval training and maximal strength training in patients with unspecific musculoskeletal disorders improve V̇O2peak and maximal strength more than moderate training.

Improving peak oxygen uptake (V̇O2peak) and maximal strength are key objectives of rehabilitation for patients with unspecific musculoskeletal disorders (MSDs). Although high-intensity training yield superior outcomes for these factors, patients with MSDs may not tolerate high-intensity due to pain and fear. Therefore, we examined the effect and feasibility of incorporating aerobic high-intensity intervals (HIITs) and maximal strength training (MST) in a standard clinical rehabilitation program for patients with unspecific MSDs. 73 patients (45 ± 10 years) with MSDs partaking in a standard, public, and 4-week rehabilitation program were randomized to high-intensity training (HG: 4 × 4 minutes intervals at ∼90% of maximal heart rate; HRmax, and 4 × 4 repetitions leg press at ∼90% of 1 repetition maximum; 1RM, with maximal intended velocity) or keep todays treatment of low-to moderate-intensity training (MG: various cycling, walking, and/or running activities at ∼70%-80% of HRmax and 3 × 8 - 10 repetitions leg press at ∼75% of 1RM without maximal intended velocity). HG improved V̇O2peak (12 ± 7%) and leg press 1RM (43 ± 34%) more than moderate-intensity group (V̇O2peak; 5 ± 6%, 1RM; 19 ± 18%, both p < 0.001). We observed that no adverse events and no between-group differences in dropout rate or self-reported quality of life (both p > 0.05). There were positive correlations between improved V̇O2peak and improved physical (p = 0.024) and emotional (0.016) role functioning. We conclude that both high-intensity interval training and MST are feasible and improve V̇O2peak and maximal strength more than standard low-to moderate-intensity treatment of patients with unspecific MSDs. Our findings suggest that high-intensity training should be implemented as a part of standard clinical care of this patient population.