Clinical Research Directory

Caffeine Supplementation and Strength Endurance in Brazilian Jiu-jitsu Athletes

This study investigated the acute effects of ingesting 400 mg of caffeine administered 30 minutes before Brazilian jiu-jitsu-specific strength endurance tests. Experienced athletes completed two conditions, placebo and caffeine, in a randomized, double-blind, crossover clinical trial. Performance was assessed using the dynamic component of the kimono grip strength test (maximum number of repetitions, MNR) and the isometric component (maximum static lift, MSL), both performed with a gi grip. Rating of perceived exertion, adverse effects, and blinding effectiveness were also evaluated.

Strength- and Velocity-Oriented Unilateral Training in Male Collegiate Team-Sport Players

This randomized, parallel-group study evaluated the effects of an 8-week unilateral resistance training program with strength- and velocity-oriented loading on limb-specific load-velocity relationships and lower-limb asymmetry in male university team-sport players. Participants were randomly assigned to a strength-oriented training group, which trained at 80% of the limb-specific one-repetition maximum (1RM), or a velocity-oriented training group, which trained at 40% of the limb-specific 1RM. Both groups completed 16 supervised free-weight split-squat training sessions over 8 weeks. In each session, the non-dominant limb performed four sets of five repetitions, while the dominant limb performed three sets of five repetitions. All repetitions were performed with maximal intended concentric velocity and real-time velocity feedback. Limb-specific load-velocity relationships were assessed at baseline, Week 4, and Week 8. Lower-limb asymmetry, balance, unilateral jump performance, and basketball-specific change-of-direction performance were assessed at baseline and Week 8. The purpose was to determine whether the two training orientations produced different adaptations and whether the additional training volume assigned to the non-dominant limb influenced inter-limb asymmetry.

Land vs. Water Exercises on Performance and Swimming Behavior in Older Adults

This study aims to investigate the effects of an 8-week combined land and aquatic exercise program (conducted 3 days per week) on physical performance, recreational swimming behaviors, and water-related risk perceptions in older adults. Physical performance is evaluated using handgrip strength and the 30-second chair sit-up test (30CST), while swimming behaviors and water-related risk perceptions are assessed via structured questionnaires.

Metformin in Elderly Patients With Type 2 Diabetes and Muscle Strength, Muscle Mass, and Physical Function: Positive or Negative Correlation?

With the accelerating aging process in China, sarcopenia has drawn increasing attention. Sarcopenia is an age-related geriatric syndrome characterized by reductions in muscle mass, muscle strength, and/or physical function. Sarcopenia has a high prevalence, often insidious onset, and broad impacts on physiological functions. According to the 2019 report from the Asian Working Group for Sarcopenia (AWGS), sarcopenia prevalence among elderly Asians ranged from 5.5% to 25.7%, with males exhibiting higher rates (5.1% to 21.0%) than females (4.1% to 16.3%). Particularly among patients with diabetes, sarcopenia incidence was significantly elevated, with a prevalence of 14.8% reported in Chinese diabetic populations. Sarcopenia exerts numerous adverse effects. Sarcopenia is strongly associated with adverse cardiovascular events and increased mortality. Sarcopenia is linked to cancer and significantly elevates the risk of various postoperative complications in patients with gastrointestinal malignancies, including dysphagia, cognitive impairment, fractures, falls, hospitalization, and all-cause mortality. Sarcopenia and diabetes frequently coexist within the same individual, leading to multiple adverse outcomes. Sarcopenia results in declining in function flexibility and responsiveness in diabetic patients, causing gait alterations and impaired balance, limiting daily activities, and is closely linked to risks of falls, fractures, depression, frailty, and mortality. Thus, it is critically important to treat sarcopenia alongside diabetes and avoid detrimental effects of hypoglycemic drugs on muscle. Metformin lowers blood glucose by increasing muscle glucose uptake, inhibiting hepatic glucose output and gluconeogenesis, and promoting glucose excretion into the intestinal lumen; it also reduces the risk of diabetic cardiovascular disease, diabetic retinopathy, nephropathy, and neuropathy. There remains controversy in current studies regarding metformin's impact on sarcopenia. Some studies indicate that metformin may have potential beneficial effects on grip strength, skeletal muscle mass, and gait speed. Nordklint AK reported that after 18 months of metformin intervention in patients with type 2 diabetes, bone mineral content and density were improved. Qaisar R conducted a 16-week metformin trial on older men, finding improvements in grip strength and gait speed with statistical significance (P \< 0.05). Klimova AV found that a 6-month metformin intervention improved physical function in patients. Lyu Q's murine study demonstrated that 5 months of metformin treatment conferred benefits and recovery effects on the gastrocnemius muscle in sarcopenia models. Conversely, some studies indicate no impact of metformin on muscle mass, grip strength, or gait speed. Qaisar R reported no improvement in body composition or gait speed after 4 months of metformin use. Laksmi PW found no significant difference in grip strength between groups after a 16-week metformin intervention. Koshizaka M reported that after 24 weeks of intervention with ipragliflozin or metformin in patients with type 2 diabetes, metformin had no significant effect on muscle mass. Previous studies have also elucidated mechanisms underlying metformin's effects on muscle. According to Kang MJ, metformin induced myostatin expression in skeletal muscle cells via the Adenosine5'-monophosphate-activated protein kinase (AMPK)-FoxO3a-HDAC6 pathway, thereby impairing muscle function. Other studies found that metformin reduced expression of mTORC1-related genes in muscles of elderly individuals with impaired glucose tolerance, potentially leading to decreased muscle protein synthesis or increased autophagy. Therefore, this study enrolled elderly patients with type 2 diabetes and employed a cross-sectional design with propensity score matching to elucidate the association between metformin and muscle strength, muscle mass, and physical function, providing evidence for rational clinical use of hypoglycemic drugs.

The Effect od Beetroot Juice on Forearm Muscle Strength and Muscle EMG Activity After BloodFlow Restriction

The primary aim of the current study is determine the effect of beetroot juice consumption on maximal grip strength and EMG muscle activity

Frailty and Muscle Strength Tests in Older Adults Undergoing Major Surgery

The goal of this observational study is to learn if simple tests for frailty and muscle strength can help predict which older adults (age 65 and older) are at higher risk for problems after major abdominal surgery. The main questions it aims to answer are: * Do measures of frailty and muscle strength, taken before surgery, predict complications after surgery? * Can these tests be easily done during a routine pre-surgical visit? Participants will: * Complete brief tests measuring muscle strength, breathing strength, physical function, nutrition status, body composition, and memory during a regular pre-surgical clinic appointment. * Allow researchers to review their medical records 30 and 90 days after surgery to identify any complications or health problems.

Swedish Physical Activity and Fitness Longitudinal Study

Aging means loss of strength, which can affect the ability to lead an active life and be independent. Physical activity can counteract the loss of strength to some extent, but individual differences are large and the mechanisms are partly unknown. The hypothesis is that changes in the innervation and composition of the muscle may explain the individual differences in strength loss. A group of Swedish men and women have participated in this study of physical performance for almost 50 years, since they were 16 years old. The project will improve the understanding of muscle aging. The findings may help to develop strategies to counteract muscle loss and enable healthy aging and to promote physical activity throughout life

Hip Thrust Versus Back Squat Training in Untrained Adults

This study compared the effects of two lower-body resistance training exercises - the barbell back squat and the barbell hip thrust - on muscle growth and strength in untrained young adults. Thirty-four participants were randomly assigned to train using either the back squat or the hip thrust, two times per week for nine weeks. Muscle size (via MRI) and strength (via weightlifting tests) were measured before and after training to determine whether one exercise produced greater improvements than the other, particularly in the gluteal muscles. Muscle activity during the first training session was also measured using surface electromyography (sEMG) to see whether early muscle activation could predict later muscle growth.

Effect of Single-Session HVPGS on Hand Grip Strength and Reaction Time in Healthy Individuals

The aim of this cross-sectional study is to investigate the immediate (acute) effects of a single session of High-Voltage Pulsed Galvanic Stimulation (HVPGS) on hand muscle strength and reaction time in healthy adults. A total of 42 healthy volunteers aged 18 to 65 years undergo a single session of HVPGS applied to the forearm flexor muscles (m. flexor digitorum superficialis, m. flexor digitorum profundus, and m. flexor pollicis longus). Isometric hand grip strength is evaluated before (T0) and immediately after (T1) the intervention using a Jamar hand dynamometer. Sensorimotor reaction time is measured at the same time points using the Nelson Hand Reaction Test. The study aims to determine whether acute HVPGS application elicits immediate bilateral enhancements in mechanical force production and central-mediated processing speed, and whether these gains interact with demographic factors or hemispheric hand dominance.

Dietary Supplements and Middle Aged Women (Collagen & Omega)

This study will examine the effects of combining different types of dietary supplements on various aspects of health and wellbeing in middle aged women. The main outcomes of the trial will be aspects of health and wellbeing that middle aged women report as increasingly problematic, such as joint pain, fatigue, sleep, and changes in body composition, strength, and inflammation. Participants will consume the supplement(s) or placebo for 8 weeks, and outcome measures will be assessed before and after supplementation.

HME Amino Acid Supplementation for Strength, Performance, and Recovery in Trained Adult Males

This pilot randomized controlled trial evaluates HME (Human Muscle Equivalent), a free-form amino acid supplement formulated to match the amino acid composition of human skeletal muscle, taken at its Health Canada licensed dose (3 g powder plus one 50 mg slow-release beta-alanine capsule daily). Trained adult males (competitive athletes or certified fitness professionals) are randomized to HME or an identical-appearing placebo for 10 weeks: a 2-week supplement-only lead-in followed by 8 weeks of supplement plus supervised resistance training. The primary aim is to estimate the effect of HME on composite maximal strength (1-repetition maximum leg press plus chest press) compared with placebo. Secondary measures include isometric knee-extension strength, countermovement jump height, and subjective recovery.

"Muscle Strength, Balance, and Core Endurance in Elite Adolescent Rowers: A Cross-Sectional Study"

This study aims to investigate the relationship between lower extremity isokinetic strength, dynamic balance, and core muscle endurance in elite adolescent rowers aged 16-18. A total of 68 athletes (32 males, 36 females) will be assessed through standardized protocols involving isokinetic testing, the Y Balance Test, and McGill Core Endurance Tests. The study aims to contribute to performance monitoring and injury prevention strategies in rowing sports.

Resistance Training Adaptations and Caffeine Intake

This parallel-group, randomized, double-blind, placebo-controlled trial investigates the effects of three different caffeine supplementation strategies on resistance training-induced adaptations in 120 caffeine-naive, inactive young adult males. Participants will undergo a 10-week supervised resistance training program. The four supplementation strategies are: (1) constant daily low-moderate dosing (4 mg/kg/day), (2) gradually escalating dose (2 to 6 mg/kg across weeks), (3) training-day-only caffeine (4 mg/kg/day), and (4) placebo. Primary outcomes include maximal strength, body composition (lean body mass and fat mass), skeletal muscle thickness, and training volume progression. Secondary outcomes include muscular endurance, jump height, flight-time-to-contraction-time (FT:CT) ratio, mechanistic/biological variables (epinephrine, norepinephrine, cortisol, testosterone, creatine kinase, IGF-1), rate of perceived exertion, sleep/recovery parameters, and adverse effects.

The Acute and Accumulative Effects of Snack Foods on Exercise Recovery

The purpose of the research is two-fold. One goal is to determine if post-exercise almond or cereal bar consumption can promote muscle gain as well as increasing muscular strength throughout an eight-week weight training program. The other goal is to assess the short-term effects of almonds or cereal bar on recovery that may explain the overall long-term adaptations.

The Impact of Trunk and Lower Extremity Electrical Stimulation on Pelvic Floor Muscle Strength in Females

This study aims to investigate the effects of whole-body electrical muscle stimulation (EMS) applied to the trunk and lower extremity muscles on pelvic floor muscle strength in healthy women. Since pelvic floor muscles are deep-seated and can be difficult to activate voluntarily, this research explores whether stimulating related muscle groups (core and legs) can provide an indirect benefit to pelvic floor strength. Participants will be divided into three groups (EMS + exercise, Sham-EMS + exercise, and exercise only) and will undergo a 6-week intervention program. Changes in pelvic floor muscle strength will be evaluated using a perineometer to determine the effectiveness of this non-invasive approach.

Ultrasound Muscle Biomarkers as Predictors of Isometric Quadriceps Muscle Strength and Handgrip in Healthy Adults: an Observational Study

This observational study aims to determine whether ultrasound-derived muscle biomarkers can predict isometric quadriceps muscle strength and handgrip in healthy adults aged 18-89 years. The main questions it aims to answer are: * Which ultrasound muscle characteristics are associated with isometric quadriceps muscle strength and handgrip? * Can ultrasound-derived biomarkers be used to develop predictive models of muscle strength in healthy adults? Participants will undergo: * Ultrasound assessment of the quadriceps and forearm flexor muscles; * Measurement of isometric quadriceps muscle strength and handgrip using standardized dynamometry protocols; * Assessment of functional capacity, mobility and balance; * Completion of questionnaires related to health status, physical activity, nutrition, fatigue and health-related quality of life. The study will also assess the reliability of ultrasound measurements and explore the relationship between ultrasound variables, muscle strength, physical function and health-related factors.

Effects of Jive Dance Training on Lower Limb Muscle Strength

The purpose of this study is to evaluate the effects of a structured, partner-free Jive dance training program on the physical and cognitive health of hospital employees. Healthcare workers often face high-stress environments, irregular shifts, and prolonged physical strain, which can lead to reduced muscle strength, poor body composition, and burnout. This study innovates by designing a solo Jive dance intervention to overcome traditional partnership limitations in workplace wellness programs. A single-group repeated measures design was used, recruiting 20 hospital employees for an 8-week study. The study was divided into Phase A (4 weeks of self-directed group practice) and Phase B (4 weeks of systematic Jive dance training). Comprehensive assessments were conducted at baseline, week 4, and week 8 to measure body composition, lower limb muscle strength, dynamic balance, working memory, and perceived stress.

Lower-Limb Muscle Mass and Cardiovascular and Muscular Performance in Males and Females

The aim of this study will be to examine the relationship between leg muscle mass and muscle strength, aerobic capacity, anaerobic power, and jumping performance in young adults. In addition, these physical performance measures will be compared between male and female participants. Recreationally active young adults will be recruited to participate in the study. Body weight and leg muscle mass will be assessed using a body composition analyzer. Participants will perform isokinetic and isometric leg strength tests, an aerobic fitness test (VO₂max), an anaerobic power test (Wingate), and a countermovement jump (CMJ) test. This study aims to improve the understanding of the effects of leg muscle mass on physical performance and to identify possible differences between males and females. The findings are expected to contribute to exercise prescription, performance assessment, and future research in sports and health sciences.

Reference Equations and Normative Data for Isometric Quadriceps and Handgrip Muscles STrength in Southern European Populations - RESTart: a Multicentre Study

This observational study aims to learn about peripheral muscle strength in healthy adults and people with chronic respiratory diseases. The study aims to develop reference data for quadriceps muscle strength and handgrip in adults living in Southern Europe and to assess whether these reference data can be used in people with chronic respiratory diseases. The main questions it aims to answer are: * What are the normal values for quadriceps and handgrip muscle strength in healthy adults aged 18-89 years living in Spain, Portugal and Italy? * Can the reference values developed in healthy adults be applied to people with chronic respiratory diseases? Participants will attend one study visit. During this visit, researchers will: * Measure quadriceps muscle strength and handgrip. * Collect information about age, sex, height, weight and other health characteristics. * Perform simple functional tests related to mobility and physical performance. * Ask participants to complete questionnaires about symptoms, physical activity and health-related quality of life.

Whey Protein and Adaptogenic Supplementation in Physically Active Females

The goal of this clinical trial is to learn whether whey protein or plant protein supplements, with or without an adaptogenic herb blend, can improve strength, recovery, stress, and wellbeing in active females. The adaptogenic blend contains ashwagandha root extract and shatavari root extract. The main questions the study aims to answer are: * Do whey protein and plant protein supplements improve muscle strength and recovery in physically active females? * Does adding ashwagandha and shatavari improve stress, recovery, sleep, and wellbeing compared with protein alone? * Are there differences between whey protein and plant protein when combined with the adaptogenic blend? Researchers will compare four supplement groups: * Whey protein * Whey protein with ashwagandha and shatavari * Plant protein * Plant protein with ashwagandha and shatavari Participants will: * Take their assigned supplement daily for 6 weeks * Attend testing sessions before and after the intervention * Complete questionnaires about recovery, sleep, stress, soreness, and digestive health * Provide saliva samples to measure stress, hormone, immune, and inflammation markers * Complete muscle strength tests, including handgrip strength and push-up testing * Complete a 24-hour dietary recall. The study includes physically active females aged 18 to 45 years who regularly participate in structured training.

Effect of Bupivacaine Liposome Injection on Muscle Strength After Total Knee Arthroplasty

This study employs a randomized controlled trial to investigate whether bupivacaine liposome injection for adductor canal block can effectively improve lower limb muscle strength after total knee arthroplasty.

Acute Effects of Proprioceptive Neuromuscular Facilitation on Hamstring-to-Quadriceps Strength Ratio

This study aimed to compare the acute effects of proprioceptive neuromuscular facilitation (PNF) and static stretching on hamstring-to-quadriceps (H/Q) strength ratios in healthy young men. A randomized crossover design was used in which participants completed both stretching protocols on separate days. Isokinetic muscle strength and H/Q ratios were assessed following each intervention. The findings provide insight into the immediate effects of different stretching modalities on muscle balance and performance.

Lower Limb Strength and Power as Predictors of Brain Blood Flow During Exercise

This study aims to investigate the predictive value of lower limb muscle strength and explosive power on exercise-induced prefrontal hemodynamic responses. Using an interpretable machine learning framework (GCAT-Net), the research analyzes how various physical performance indicators-such as isokinetic muscle strength, 1RM leg press, and vertical jump metrics-can predict oxygenated hemoglobin (ΔHbO) changes in the bilateral dorsolateral prefrontal cortex (DLPFC) during moderate-intensity cycling.

Effects of Six-Week Accentuated Eccentric Load Training on Balance and Strength in Young Football Players

This study aims to investigate the effects of a structured training intervention on selected physical performance parameters in athletes. The primary objective is to determine whether the intervention leads to measurable improvements in performance outcomes such as balance, strength, sprint, change of direction, or jump performance. Participants will undergo baseline performance assessments before the intervention period. Following the baseline testing, participants will complete a supervised training program lasting several weeks. After the intervention, the same performance tests will be repeated under standardized conditions to evaluate changes in performance. All assessments will be conducted by trained researchers using validated measurement tools in a controlled training environment. The findings of this study are expected to provide evidence regarding the effectiveness of the training intervention and contribute to the development of evidence-based training strategies for athletes.