[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"health-study-detail:100654251":3},{"organization":4,"outcomesModule":7,"designInfo":23,"detailedDescription":29,"studyPopulation":22,"armGroups":30,"interventions":45,"overallOfficials":52,"centralContacts":56,"locations":62,"responsibleParty":74,"collaborators":22,"id":77,"slug":78,"hasResults":79,"nctId":80,"briefTitle":81,"officialTitle":82,"acronym":22,"eligibilityCriteria":83,"healthyVolunteers":84,"sex":85,"minAge":86,"maxAge":87,"enrollmentInfo":88,"targetDuration":22,"studyType":91,"phases":92,"briefSummary":94,"conditions":95,"keywords":98,"overallStatus":105,"whyStopped":22,"lastUpdateSubmitDate":106,"lastUpdatePostDateStruct":107,"startDateStruct":110,"completionDateStruct":112,"leadSponsor":114,"locationsCount":115},{"fullName":5,"class":6},"Bitlis Eren University","OTHER",{"primaryOutcomes":8,"secondaryOutcomes":22,"otherOutcomes":22},[9,13,16,19],{"measure":10,"description":11,"timeFrame":12},"Linear Sprint Performance (5m, 10m, and 15m Sprint Times)","Linear sprint performance measured over 5 meters (acceleration), 10 meters, and 15 meters using a high-precision wireless photocell timing system. Times are measured in seconds (s), where lower values indicate better sprint performance.","Baseline (Pre-test) and 8 weeks (Post-test)",{"measure":14,"description":15,"timeFrame":12},"Squat Jump (SJ) Height","Lower-limb concentric explosive power output measured via Squat Jump test on a digital contact mat\u002Fforce platform. Surcharge from arm swing is isolated by keeping hands on hips. Jump height is measured in centimeters (cm), where higher values indicate greater explosive power output.",{"measure":17,"description":18,"timeFrame":12},"Countermovement Jump (CMJ) Height","Stretch-shortening cycle (SSC) performance and lower-limb reactive power measured via Countermovement Jump test on a digital contact mat\u002Fforce platform. Jump height is recorded in centimeters (cm), where higher values represent superior vertical jump capacity.",{"measure":20,"description":21,"timeFrame":12},"Reactive Strength Index (RSI)","Reactive strength capacity and neuromuscular stiffness assessed via Drop Jump (DJ) test from a 30 cm box. Calculated as jump height (meters) divided by ground contact time (seconds) \\[RSI = Jump Height (m) \u002F Contact Time (s)\\]. Higher index scores reflect better reactive strength and shorter contact time.",null,{"allocation":24,"interventionModel":25,"interventionModelDescription":26,"primaryPurpose":6,"observationalModel":22,"timePerspective":22,"maskingInfo":27},"RANDOMIZED","PARALLEL","A parallel-group, randomized experimental field design with three active intervention groups (10% BW, 15% BW, and 20% BW sled towing loads). Participants are stratified and allocated into homogeneous groups based on baseline 15-meter sprint performance. All groups receive their respective resisted sprint protocols twice weekly over an 8-week period while maintaining identical overall external training volume, sprint distance (15 m), and rest intervals.",{"masking":28,"maskingDescription":22,"whoMasked":22},"NONE","Background and Rationale:\n\nSprint performance, acceleration capacity, and change of direction speed are key determinants of athletic success in association football. The age period of 13-14 years represents a \"critical window of opportunity\" characterized by rapid adaptations in neuromuscular control, motor unit recruitment, and myelination. Resisted sprint methods, particularly sled towing, allow athletes to overload horizontal force production at sprint-specific joint angles without altering overall running kinematics. However, there is a methodological gap in the literature regarding the optimal and safe acute load prescription (%BW) for pediatric and youth populations.\n\nStudy Design and Methodology:\n\nThis study is an 8-week, parallel-group randomized controlled field trial involving 30 licensed male youth football players. Participants are randomly allocated into three homogeneous intervention groups using a stratified block randomization method based on baseline 15-meter sprint performance:\n\nLight Load Group: Sled towing with 10% Body Weight (BW)\n\nModerate Load Group: Sled towing with 15% Body Weight (BW)\n\nHeavy Load Group: Sled towing with 20% Body Weight (BW)\n\nTraining Protocol:\n\nSled sprint training sessions will be conducted twice per week (minimum 48 hours of recovery between sessions) over 8 weeks (16 total sessions) at the beginning of regular football practice, immediately following a standardized 15-18 minute warm-up protocol. Running distance (15 meters per repetition), inter-repetition rest (2 minutes), and inter-set rest (3 minutes) will be held constant across all groups. Training progression will be achieved through gradual volume increases:\n\nWeeks 1-2: 2 sets × 3 reps (90 m\u002Fsession)\n\nWeeks 3-4: 2 sets × 4 reps (120 m\u002Fsession)\n\nWeeks 5-6: 3 sets × 3 reps (135 m\u002Fsession)\n\nWeeks 7-8: 3 sets × 4 reps (180 m\u002Fsession)\n\nOutcome Assessments:\n\nBaseline (pre-test) and post-intervention (post-test) evaluations will be conducted on non-fatigued days. Primary outcome measures include:\n\nSprint Performance: Linear sprint times over 5m, 10m, and 15m measured using a high-precision wireless photocell timing system.\n\nNeuromuscular Performance: Vertical jump heights (cm) assessed via Squat Jump (SJ) and Countermovement Jump (CMJ) tests on a digital contact mat\u002Fforce platform.\n\nReactive Strength: Drop Jump (DJ) test from a 30 cm box to calculate the Reactive Strength Index (RSI = jump height \u002F contact time).",[31,37,41],{"label":32,"type":33,"description":34,"interventionNames":35},"Light Sled Load Group (10% BW)","EXPERIMENTAL","Participants perform resisted sprint training using a sled loaded with 10% of their individual body weight (BW). Training is performed 2 sessions\u002Fweek for 8 weeks (16 sessions) over 15 meters with standardized progression (2-3 sets, 3-4 reps, 2 min inter-repitition rest, 3 min inter-set rest).",[36],"Other: Resisted Sled Sprint Training",{"label":38,"type":33,"description":39,"interventionNames":40},"Moderate Sled Load Group (15% BW)","Participants perform resisted sprint training using a sled loaded with 15% of their individual body weight (BW). Training is performed 2 sessions\u002Fweek for 8 weeks (16 sessions) over 15 meters with standardized progression (2-3 sets, 3-4 reps, 2 min inter-repitition rest, 3 min inter-set rest).",[36],{"label":42,"type":33,"description":43,"interventionNames":44},"Heavy Sled Load Group (20% BW)","Participants perform resisted sprint training using a sled loaded with 20% of their individual body weight (BW). Training is performed 2 sessions\u002Fweek for 8 weeks (16 sessions) over 15 meters with standardized progression (2-3 sets, 3-4 reps, 2 min inter-repitition rest, 3 min inter-set rest).",[36],[46],{"type":6,"name":47,"description":48,"armGroupLabels":49,"otherNames":50},"Resisted Sled Sprint Training","An 8-week periodized resisted sprint training protocol using weighted sleds. Sessions are performed twice weekly over a 15-meter sprint distance, immediately following a standardized warm-up. Participants are assigned to sled towing loads equivalent to 10%, 15%, or 20% of their individual body weight (BW). Training volume progresses systematically from 2 sets of 3 repetitions (Weeks 1-2) to 3 sets of 4 repetitions (Weeks 7-8) with 2 minutes of inter-repetition rest and 3 minutes of inter-set rest.",[42,32,38],[51],"Sled Towing",[53],{"name":54,"affiliation":5,"role":55},"Muhammed Z Kahraman, PhD","PRINCIPAL_INVESTIGATOR",[57],{"name":54,"role":58,"phone":59,"phoneExt":60,"email":61},"CONTACT","00904342220000","8113","mzkahraman@beu.edu.tr",[63],{"facility":5,"status":22,"city":64,"state":65,"zip":66,"country":67,"countryCode":22,"cosmosGeoPoint":68,"geoPoint":73,"contacts":22},"Bitlis","Central","13000","Turkey (Türkiye)",{"type":69,"coordinates":70},"Point",[71,72],42.10784,38.40115,{"lat":72,"lon":71},{"type":55,"investigatorFullName":75,"investigatorTitle":76,"investigatorAffiliation":5,"oldNameTitle":22,"oldOrganization":22},"Muhammed Zahit Kahraman","Associate Professor, Department of Coaching Education, Faculty of Sport Sciences, Bitlis Eren University","100654251","effects-of-different-sled-loads-on-sprint-and-neuromuscular-performance-in-young-male-football-players-an-8-week-periodized-field-study-100654251",false,"NCT07797920","Effects of Different Sled Loads on Sprint and Neuromuscular Performance in Young Male Football Players: An 8-Week Periodized Field Study","Effects of Different Sled Towing Loads on Sprint Mechanics, Acceleration, and Neuromuscular Performance in Young Male Football Players: An 8-Week Periodized Field Trial","Inclusion Criteria:\n\n* Male football players aged chronologically between 13 and 14 years.\n* Minimum of 2 years of active, licensed competitive football experience in a club or academy.\n* Regular attendance at scheduled team training sessions.\n* Written Informed Consent\u002FAssent signed by both the participant (Child Assent Form) and parent\u002Flegal guardian (Parental Consent Form).\n* Free of severe lower-limb musculoskeletal injuries (e.g., ligament tears, fractures, meniscus injuries) in the past 6 months.\n\nExclusion Criteria:\n\n* Chronological age \\\u003C13 or \\>14 years.\n* Presence of chronic, cardiovascular, metabolic, or respiratory conditions (e.g., asthma) that pose risks during high-intensity maximal exercise.\n* Regular use of performance-enhancing supplements or medications affecting physiological and neuromuscular responses.\n* Absence from more than 10% of prescribed sled training sessions (2 or more sessions out of 16).\n* Failure to complete pre- or post-intervention performance testing batteries, or failure to demonstrate maximal effort during testing.\n* Concurrent participation in external individual strength, speed, or fitness programs outside the football academy.",true,"MALE","13 Years","14 Years",{"count":89,"type":90},30,"ESTIMATED","INTERVENTIONAL",[93],"NA","The purpose of this 8-week periodized field study is to investigate and compare the acute and chronic effects of three different sled towing loads (10%, 15%, and 20% of body weight \\[BW\\]) on sprint performance (5m, 10m, 15m) and neuromuscular characteristics (Squat Jump \\[SJ\\], Countermovement Jump \\[CMJ\\], Drop Jump \\[DJ\\], and Reactive Strength Index \\[RSI\\]) in trained male youth football players aged 13-14 years. While all other training variables (distance, frequency, volume, and rest intervals) are standardized, this study aims to identify the optimal sled load that enhances acceleration and horizontal force production without compromising running mechanics during a critical pediatric athletic development window.",[96,97],"Athletic Performance","Neuromuscular Adaptations",[99,100,101,102,103,104],"Sled towing","Resisted sprint training","Youth football","Neuromuscular performance","Reactive Strength Index","Acceleration","NOT_YET_RECRUITING","2026-08-27",{"date":108,"type":109},"2026-09-01","ACTUAL",{"date":111,"type":90},"2026-09-05",{"date":113,"type":90},"2026-11-15",{"name":5,"class":6},1]