Clinical Research Directory

Effects of Small-Sided Games and Repeated Sprint Training in Young Soccer Players

The purpose of this study is to compare the effects of 6-week Small-Sided Games (SSG) and Repeated Sprint Training (RST) on body composition, anaerobic power, and selected physical performance qualities in young male soccer players. A total of 24 active male soccer players (aged 16 to 20 years) participating in the Regional Amateur League were randomly assigned into three equal groups: Small-Sided Games Group (SSGG) completing a 4 vs. 4 transition possession game 3 days a week in addition to routine training, Repeated Sprint Training Group (RSTG) completing a 20-meter maximal repeated sprint protocol 3 days a week in addition to routine training, and Control Group (CG) continuing only their routine soccer practice schedule. Before and after the 6-week intervention, participants underwent laboratory and field testing to evaluate body composition (body fat percentage, fat-free mass, BMI), acceleration and maximal speed (10m and 20m sprint tests), agility (Illinois Agility Test), explosive lower-body power (countermovement jump), and maximal anaerobic power (30-second Wingate test) to determine which specific training method provides superior athletic adaptations.

Phosphatidylserine, Taurine, and Caffeine for Cognitive Fatigue in Professional Football Players

This randomized, double-blind, placebo-controlled, parallel-group trial will evaluate neurocognitive fatigue resistance and football-specific decision-making following 28 days of taurine-caffeine supplementation with or without phosphatidylserine in professional male football players. Sixty-two male outfield football players from two professional clubs will be randomized to placebo, taurine plus caffeine, or taurine plus caffeine plus phosphatidylserine. Neurocognitive fatigue resistance will be evaluated during a standardized high-load Stroop/Flanker task, while football-specific tactical decision-making, visual-search behavior, and field-based reactive decision performance will be assessed at baseline and after 28 days of supplementation.

TCP-600 Supplementation and Performance Response in Professional Football Players

This study will examine whether a 28-day supplementation protocol containing taurine, caffeine, and phosphatidylserine can help professional male football players maintain physical performance, cognitive function, recovery-related readiness, and selected football-specific perceptual-cognitive performance. Participants will be randomly assigned to receive either placebo or a phosphatidylserine-containing multi-ingredient supplement. Before and after the supplementation period, players will complete non-invasive assessments such as sprint testing, reaction-time testing, heart rate variability monitoring, wellness/readiness questionnaires, mental-fatigue measures, and selected football-specific perceptual-cognitive tasks where available. The study is designed as an external validation and extension of responder profiles derived from previous randomized controlled trials. Data from previous trials and this validation cohort will be used to examine whether baseline physical, cognitive, autonomic, fatigue-related, recovery-related, or perceptual-cognitive characteristics can predict which players are most likely to benefit from phosphatidylserine-containing multi-ingredient supplementation.

Effects of 8-Week TRX Suspension Training on Body Composition, Anaerobic Power, and Biomotor Abilities in Young Male Volleyball Players

The purpose of this study was to examine the effects of an 8-week TRX suspension training program on body composition, anaerobic power, and selected biomotor abilities in young male volleyball players. A total of 26 male volleyball players (aged 14-18 years) were randomly assigned into two groups: an Experimental Group (n = 13) and a Control Group (n = 13). The control group participated solely in their routine volleyball training sessions, while the experimental group performed TRX suspension training twice a week in addition to their routine volleyball training over the 8-week period. Pre- and post-intervention evaluations included body composition metrics, anaerobic power (Wingate anaerobic test), vertical jump height, handgrip strength, leg strength, and a 10-meter sprint test. The findings aim to provide evidence on the efficacy of suspension training for physical performance adaptation in youth volleyball athletes.

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.

Core Strength Training, Anthropometry, and Postural Control in Youth Optimist Sailors

Optimist dinghy sailing is a highly demanding youth watersport characterized by prolonged, high-intensity isometric hiking postures and rapid dynamic weight shifts required to preserve boat trim, balance, and sail power output. The core (lumbar-pelvic-hip complex) functions as the central dynamic link in transferring kinetic forces between the lower limbs and trunk during continuous open-water maneuvers. This study is designed as a 12-week randomized controlled interventional trial to evaluate the effects of a periodized, circuit-based Core Strength Training (CST) program integrated into routine Technical Sailing Training (TST) compared to TST alone. Primary endpoints evaluate adaptations in the anthropometric profile (skinfold thickness, circumferences, muscle mass percentage) and postural control parameters (Center of Pressure displacement and sway velocity measured via computerized force platform posturography) in competitive youth Optimist sailors.

ACL Mechanical Property Changes in Female Collegiate Basketball Players During a Competitive Season

This prospective cohort study aims to investigate whether the mechanical properties of the anterior cruciate ligament (ACL) undergo measurable changes throughout a competitive basketball season in female collegiate athletes. Female athletes are at a significantly higher risk for non-contact ACL injuries compared to males. Beyond acute injuries, cumulative stress from high-intensity sports may lead to subclinical alterations in the ligament's biomechanical properties, potentially increasing injury risk. Using non-invasive shear wave elastography (SWE) and countermovement jump (CMJ) tests, the study will monitor 60 elite players before and after the University Basketball League (UBL) season. The findings will help identify potential signs of cumulative loading and contribute to the development of early detection markers for injury risk in female athletes.

Neuro-Athletic Training on Goalkeeper Performance

This randomized controlled trial investigated the effects of an 8-week neuro-athletic training (NAT) program on dynamic balance, explosive strength, grip strength, and agility in elite soccer goalkeepers. Participants were randomly assigned to either an experimental group receiving NAT in addition to regular training or a control group continuing standard training. Pre- and post-intervention performance assessments were conducted to determine the effectiveness of the intervention.

Respiratory Muscle Strength and Jiu-Jitsu-Specific Performance in Male Brazilian Jiu-Jitsu Athletes

Brazilian Jiu-Jitsu (BJJ) is an intermittent combat sport that requires repeated high-intensity efforts and sustained gripping. This analytical cross-sectional study will examine whether respiratory muscle strength is associated with BJJ-specific anaerobic performance and static kimono grip endurance in adult male BJJ athletes. Forty athletes will attend three assessment visits separated by 48 to 72 hours. Maximal inspiratory pressure, maximal expiratory pressure, and spirometric indices (forced vital capacity \[FVC\], forced expiratory volume in 1 second \[FEV1\], FEV1/FVC ratio, and peak expiratory flow \[PEF\]) will be measured at the first visit. The Jiu-Jitsu Anaerobic Performance Test and the Maximum Static Kimono Grip Test will be completed at the other two visits in randomized order. The primary analysis will examine the association between maximal inspiratory pressure and the total number of valid repetitions completed during the Jiu-Jitsu Anaerobic Performance Test. Spirometric indices will be evaluated as secondary outcomes.

Endurance Trial: Ketone and Carbohydrate Supplementation

This randomized, double-blind, crossover study investigates the effects of exogenous ketone supplementation on physical and cognitive performance in amateur endurance athletes during exhaustive exercise. Participants will complete three 3-hour cycling sessions under different nutritional conditions: carbohydrate alone (CHO), carbohydrate plus ketone (CHO-KET), and placebo (PLA). The study will assess cognitive function through validated computerized tests, physical performance via distance covered, and metabolic responses through blood biomarkers. Additionally, peripheral blood mononuclear cells (PBMCs) will be collected and cultured with LPS or not. Other PBMCs co-cultured with neuronal cells (SH-SY5Y) to investigate neuro-immune interactions. The primary hypothesis is that ketone supplementation will preserve cognitive function and enhance physical performance during prolonged exhaustive exercise compared to carbohydrate supplementation alone, potentially through anti-inflammatory mechanisms and alternative energy substrate provision.

Acute Effects of a Brief Low-Load Core Activation Warm-Up on Football-Specific Technical Performance in Male Youth Players

This study examined whether a brief, low-load core activation warm-up would acutely improve football-specific technical performance compared with a conventional dynamic warm-up in male youth football players. Twenty-four players (aged 15-16 years) completed both warm-up conditions in a single-session, counterbalanced crossover design separated by a 10-minute passive recovery period. Following each warm-up, players performed standardised tests of dribbling speed, passing accuracy, shooting accuracy, and ball control. The study was designed as an exploratory pilot to estimate effect sizes and inform the design of a future definitive trial.

Cluster Training With Blood Flow Restriction in Competitive 200-m Freestyle Swimmers

This study evaluated whether adding blood flow restriction (BFR) to cluster-based training could improve swimming performance and selected physiological responses in competitive swimmers. Twenty competitive swimmers were assigned using a matched, non-randomized design to either an experimental group performing cluster training combined with BFR or a control group performing the same cluster training without BFR. The intervention lasted 8 weeks, with five training sessions per week. The primary outcome was 200-m freestyle performance time. Secondary outcomes included serum concentrations of fibroblast growth factor-2 (FGF-2) and vascular endothelial growth factor-A (VEGF-A), standing long jump performance, mean 50-m split time during a 150-m swimming test, and repetitions completed during a cadence-controlled Burpee test. The study was designed to determine whether BFR provided additional performance and physiological benefits beyond cluster training alone.

Strong Kinesio Taping and Shoulder Performance

This study evaluated the immediate effects of Strong Kinesio Taping on shoulder muscle performance in professional male basketball players. The study used a randomized crossover design in which each participant completed three experimental conditions: Strong Kinesio Taping, sham taping, and no taping. The testing sessions were separated by a 72-hour washout period. During each session, the internal and external rotator muscle performance of the dominant shoulder was assessed using an isokinetic dynamometer at angular velocities of 60°/s and 240°/s. The main outcomes were peak torque and total work of the shoulder internal and external rotator muscles. The external-to-internal rotator strength ratio was also evaluated to determine whether taping affected the balance between these muscle groups.

Cluster Training in Female Volleyball Players

This study compares the effects of three different resistance training methods-traditional training, standard cluster training, and undulating cluster training-on strength, hormonal responses, and inflammation in female volleyball players aged 18-30 years. Thirty participants with at least two years of volleyball and resistance training experience were randomly assigned to one of three groups. All participants performed resistance training three times per week and volleyball-specific training two times per week for eight weeks. Blood samples were taken before and after the first session (acute response) and after eight weeks (chronic adaptation) to measure testosterone, cortisol, IGF-1, progesterone, and C-reactive protein (CRP). Performance tests included upper-body and lower-body strength (bench press and squat), speed, agility, and vertical jump. The main finding was that undulating cluster training produced significantly greater improvements in upper-body strength compared to standard cluster training, while all three methods were equally effective for lower-body strength and other performance measures. No significant differences were found between groups for hormonal or inflammatory changes. The study provides practical guidance for coaches seeking to optimize upper-body strength gains in female volleyball players.

Life Skills Training for Anxiety and Football Performance in Adolescent Players

This randomized behavioral study will evaluate whether an eight-week life skills training program will reduce cognitive sport anxiety and improve football performance in non-elite adolescent football players in China. A total of 160 players aged 14 to 17 years from 16 teams will be allocated individually within team-by-gender strata to either a life skills training group or a usual-training control group. The intervention will include 16 small-group sessions delivered twice per week for 45-60 minutes. Assessments will be conducted at baseline, immediately after the eight-week intervention, and four weeks later. The primary psychological outcome will be cognitive anxiety derived from the Worry and Concentration Disruption subscales of the Sport Anxiety Scale-2. The primary performance outcome will be a baseline-referenced Football Performance Index derived from passing accuracy, shooting accuracy, dribbling time, and agility time. The study hypothesis is that life skills training will reduce cognitive anxiety and improve football performance, and that greater reduction in cognitive anxiety immediately after the intervention will be associated with better football performance at follow-up.

Bench Press During Squat Conditioning and PAPE

The goal of this clinical trial is to learn whether adding a moderate-load bench press exercise during the recovery periods between sets of back squats affects subsequent jumping performance in competitive male basketball players. The main questions it aims to answer are: Does adding bench press exercise during recovery periods affect countermovement jump height following the squat conditioning activity? Does adding bench press exercise affect the timing and magnitude of the post-activation performance enhancement response? Researchers will compare a squat-only group with a squat plus bench press group to see if performing bench press exercise during the recovery periods affects subsequent jumping performance. Participants will: Perform three sets of three back squat repetitions at 85% of their one-repetition maximum, with 3-minute recovery periods between sets. Participants in the squat plus bench press group will additionally perform three bench press repetitions at 75% of their one-repetition maximum during the recovery periods. Perform countermovement jumps before the conditioning activity and 3, 6, 9, and 12 minutes after the final squat set.

The Impact of the Menstrual Cycle on Physical Exercise and Performance

The menstrual cycle implies a basic difference in the biology of women and men but the effect of the hormonal variation on training protocols and physical performance is still not fully understood. Despite no existing evidence, the advice to periodize exercise according to the menstrual cycle has been widely spread among elite athletes, coaches, and sports federations. The advice is based on underpowered studies with considerable methodological weaknesses regarding determination of cycle phase, inclusion of athletes and lack of adequate control groups. The purpose of this randomized, controlled study is to evaluate the effect of exercise periodization on aerobic fitness during different phases of the menstrual cycle. Further, the effect will be related to premenstrual symptoms, body composition and skeletal muscle morphology, sex hormone receptors, metabolic enzymes, and markers of muscle protein synthesis. This study will be well controlled and follow methodology recommendations for menstrual cycle research in sports and exercise. Female athletes of fertile age will be randomized to different training regimens during three menstrual cycles (12 weeks): Group A: Training three times a week throughout the menstrual cycle. Group B: Follicular phase-based training five times a week during the follicular phase and thereafter once a week during the luteal phase. Group C: Luteal phase-based training five times a week during the luteal phase and once a week in the follicular phase. The exercise will consist of high intensity intermittent spinning classes. Assessment of aerobic fitness and power will be performed at baseline, and again after three completed menstrual cycles. On the same day, body composition will be examined by DXA and blood samples will be collected for analysis of hormones and binding proteins. To confirm menstrual cycle phase, blood samples will be collected for hormone determination, and urinary stick will be used for detection of ovulation. Subjective ratings of menstrual cycle related symptoms will be performed every day. In a subgroup of women, muscle biopsies will be collected from m vastus lateralis at baseline and at the end of the study. This study will contribute to improved knowledge about exercise periodization in relation to the menstrual cycle. Well-grounded data is crucial to give evidence-based recommendations to female athletes when planning their training protocol to optimize training results and performance.

Effects of Unilateral Compound Training on Lower-Limb Strength Asymmetry and Athletic Performance in Female Handball Players

Lower-limb strength asymmetry is common among female handball players and may negatively affect athletic performance while increasing injury risk. This randomized controlled trial was designed to investigate the effects of a six-week unilateral compound training program on lower-limb strength asymmetry, isokinetic muscle strength, hamstring-to-quadriceps ratio, body composition, and physical performance in competitive female handball players. Participants were randomly assigned to either an experimental group receiving unilateral compound training in addition to regular handball training or a control group continuing regular handball training only. It was hypothesized that unilateral compound training would reduce strength asymmetry and improve neuromuscular performance compared with regular training alone.

Critical Thinking Tactical Training in University Futsal Players

This study examined the effects of a tactical training program based on critical thinking (TPCT) on the tactical efficiency and decision-making performance of university futsal players. The intervention was designed to strengthen players' ability to interpret the dynamics of play, anticipate opponents' actions, and generate adaptive tactical responses under competitive conditions. The program followed a socio-constructivist framework, promoting learning through problem solving and interaction among teammates. Training sessions combined representative game situations, reflective questioning, and guided tactical discussions. A single-group pre-post design was implemented. Thirteen university players participated voluntarily after providing informed consent and receiving approval from the institutional ethics committee. Data were collected before and after the intervention to assess individual and collective tactical performance, goal effectiveness, and time of ball possession. The study aimed to provide evidence on the educational and performance impact of a critical thinking-based tactical approach in futsal, contributing to contemporary models of athlete development and pedagogical innovation in team sports.

High-Intensity Interval Training Effects on Fitness in Youth Soccer Players

This study aims to investigate the effects of an 8-week high-intensity interval training (HIIT) program on aerobic capacity, anaerobic power, blood lactate levels, and sprint performance in young male soccer players. Twenty-four volunteer U19-category soccer players from Sivasspor A.Ş. were randomly allocated into an experimental group (n=12), which performed HIIT three days per week for 8 weeks in addition to their regular training, and a control group (n=12), which continued only their routine training program. Anthropometric measurements, resting heart rate, aerobic performance (Yo-Yo IRT1), anaerobic performance (RAST), and blood lactate levels were assessed before and after the intervention period.

Effects of Mental Fatigue Duration on Cortical Activity and Jump Performance

"This study investigates whether the length of time spent on a mentally demanding task affects brain activity and jumping performance in physically active young men. Twelve healthy male university students, all regularly engaged in sport, completed four separate testing sessions on different days, each at least 72 hours apart. In one session (the control condition), participants watched a calm nature documentary. In the other three sessions, mental fatigue was induced by having participants perform a demanding attention task (the Stroop color-word test) continuously for 10, 15, or 30 minutes. Before and after each session, brain activity was recorded using electroencephalography (EEG), a painless method that measures electrical activity through sensors placed on the scalp. Immediately afterward, participants performed a countermovement jump test, a standard measure of explosive leg power used in sports science. The study examines whether longer periods of mental fatigue produce progressively larger changes in brain activity and jump performance, and whether changes in brain activity are related to changes in jumping ability. The findings may help athletes, coaches, and students better understand how mentally tiring activities, such as studying or exams, could affect physical performance shortly afterward."

Priming Using Contrast Training Exercise

This study investigated the effects of a morning complex-contrast training session on afternoon sport-specific and physical performance in competitive judokas. The study focused on identifying whether a stimulus targeting both force and velocity components of the force-velocity curve could induce a "delayed potentiation" effect 6 hours later and whether these responses differed by sex.

The Effects of Acute Nitrate and Caffeine Co-ingestion on Discipline-Specific Exercise Performance.

The purpose of this study is to investigate the acute, separate, and combined ergogenic effects of dietary nitrate (beetroot juice, BJ) and caffeine (CAF) supplementation on discipline-specific athletic performance. The project employs a double-blind, randomized, placebo-controlled, four-arm crossover design. It evaluates two highly distinct, heterogeneous populations of athletes: (A) adult high-intensity functional training (HIFT/CrossFit/Hyrox) competitors performing the standardized Hyrox Physical Fitness Test (P'F'T), and (B) elite junior competitive swimmers (National Team members) performing a progressive 8 × 100 m swimming test. The study will assess physical performance, lactate kinetics, subjective exertion, biochemical indices, psychological metrics, and gastrointestinal tolerance.

The Effect of Cold Water Immersion on Recovery and Performance in NCAA Division I Athletes

In this study, the investigators will examine the effect of cold-water immersion (CWI) on objective and subjective recovery metrics, as well as simple performance metrics, in National Collegiate Athletics Association (NCAA) Division I Men's and Women's Volleyball players, Men's Football players, and Men's and Women's Cross Country runners. This is a cohort cross-over study that will take place over the course of four weeks during an intensive training cycle. Participants will wear a WHOOP monitoring device on their wrists at all times during the study period. The two-week intervention will consist of ten minutes of CWI to take place within one hour of the completion of the last training session of the day. The target water temperature will be 55 degrees Fahrenheit, and each participant will complete five sessions of CWI per week (for a total of ten sessions over the two-week intervention phase). Objective recovery measures will include heart rate variability, resting heart rate, total sleep time, slow wave sleep time, sleep consistency, blood oxygenation, and nocturnal skin temperature, all of which will be collected continuously by the WHOOP monitoring device. Subjective recovery measures will include three surveys to be completed daily, including the Likert Scale of Muscle Soreness, the Total Quality Recovery Scale, and the Single-Item Sleep Questionnaire. Performance measures will include a counter-movement jump to be completed two times per week, an isometric mid-thigh pull to be completed once per week, and a drop jump to be completed once per week. These outcome measures will similarly be collected during the two-week control period, during which participants will not have access to CWI following training sessions.