Adolescent Athletic Performance, Flexibility, Stretching Exercises, Sports Physical Therapy, Martial Arts
Conditions
Keywords
Adolescent Athletic Performance, Flexibility, Stretching Exercises, Sports Physical Therapy, Martial Arts
Brief summary
This randomized single-blind crossover trial investigated the acute effects of three different exercise modalities, namely self-myofascial release with a foam roller, dynamic stretching, and static stretching, on posture, flexibility, dynamic balance, and lower-extremity performance in adolescent karate athletes (12-18 years). Participants attended four weekly sessions at the same time of day and after a 48-hour rest period. In the first week a baseline (control) measurement was performed, and in the following three weeks each participant received the three interventions in a randomized order. Outcomes included a four-view smartphone-based posture analysis (PostureScreen Mobile), the Sit-and-Reach Test, the Y Balance Test, the 30-second Sit-to-Stand Test, and the Vertical Jump Test (My Jump Lab 2). The aim was to identify which warm-up modality offers the greatest acute benefit before karate-specific performance
Detailed description
Design: This study was a randomized, single-blind, three-period crossover trial conducted at the Usak Karate Ozlem Sport Club, Usak, Turkiye. Adolescent karate athletes aged 12-18 years training at least 4 days/week and a minimum of 10 hours/week were eligible. After signing the assent and parental informed consent forms, participants were randomly allocated to one of three treatment-order sequences using sealed opaque envelopes. Procedures: All assessments and interventions were carried out by the same physiotherapist on the same day of the week, with one-week wash-out periods between sessions, and after a 48-hour abstention from training in order to capture purely acute effects. Week 1 served as the control measurement (no intervention). In Weeks 2-4, the three interventions (static stretching, dynamic stretching, self-myofascial release) were applied in a randomized order; outcome measures were repeated immediately after each intervention with a standardized 2-minute rest interval. Interventions: (1) Static stretching: 30-second hold per muscle group (knee flexors, knee extensors, hip extensors), 5 repetitions, with 15-second inter-set rest. (2) Dynamic stretching: walking knee-to-chest, walking quadriceps stretch (heel-to-buttock), and walking straight-leg kicks; each performed for 30 seconds (one repetition every 2 seconds), 5 sets with 15-second inter-set rest. (3) Self-myofascial release (SMR): EVA medium-density foam roller applied to knee extensors, knee flexors, and hip extensors; 5 sets of 30 seconds at 40-60 bpm rolling cadence per muscle group. Outcome assessment: Posture was evaluated with the PostureScreen Mobile (PSM) application using anterior, posterior, right and left lateral photographs and analyzing head, shoulder, pelvis and knee anterior/lateral translations. Flexibility was assessed using the Sit-and-Reach Test on a standard reach box. Dynamic balance was assessed with the Y Balance Test (anterior, posteromedial, posterolateral reach distances normalized to leg length) on both lower extremities. Lower-extremity muscular endurance was assessed with the 30-second Sit-to-Stand Test. Vertical jump performance was measured using the My Jump Lab 2 smartphone application with a tripod-fixed iPhone camera. Statistical analysis: A priori power analysis was performed using G\*Power 3.1 (effect size f = 0.25, alpha = 0.05, power = 0.95) which yielded a minimum required sample of 36 participants; 48 athletes were enrolled to account for potential drop-outs. Normality was tested with the Shapiro-Wilk test. Because data were not normally distributed, the Friedman test was used for within-subject comparisons, with Wilcoxon signed-rank tests applied for pairwise post-hoc analyses. A change-score (delta) analysis was used to compare interventions head-to-head. Statistical analyses were performed using IBM SPSS 25.0 with significance set at p\<0.05. There was no external funding for the study and the authors declared no conflicts of interest.
Interventions
BEHAVIORALStatic Stretching
Single-session static stretching protocol for the lower-extremity (knee flexors, knee extensors, hip extensors): 30-second hold x 5 repetitions x 15-second rest, performed under physiotherapist supervision.
BEHAVIORALDynamic Stretching
Single-session dynamic stretching protocol targeting the hip flexors/extensors and knee flexors/extensors with continuous walking-based movements; 30 seconds x 5 sets per exercise with 15-second rest, performed under physiotherapist supervision.
BEHAVIORALSelf Myofascial Release
Self-myofascial release applied with a medium-density EVA foam roller. Each lower-extremity muscle group received 5 sets of 30-second rolling at 40-60 bpm, with 4-second forward-and-back rolling cycles, performed under physiotherapist supervision
Sponsors
Istinye University
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
OTHER
Masking
SINGLE (Subject)
Masking description
Every participant complete all interventions with different order. They only informed about all interventions causes relaxation on muscles. Thet don't informed about which one is probably more effective.
Intervention model description
Randomized single-blind three-period crossover trial; each participant received all three interventions in a randomized order with one-week wash-out periods.
Eligibility
Sex/Gender
ALL
Age
12 Years to 18 Years
Healthy volunteers
Yes
Inclusion criteria
* Age 12-18 years. * Active karate training of at least 4 days per week and at least 10 hours per week. * Ability to communicate in Turkish or English (written and verbal). * Written informed assent of the participant and informed consent of the parent/legal guardian.
Exclusion criteria
* Any systemic, orthopedic, neurologic, chronic or psychiatric disease. * Any health problem precluding regular training participation. * Long-term steroid use. * Use within the past 48 hours of medications known to influence musculoskeletal performance. * During the study: pain greater than 3/10 on the VAS, intercurrent illness or injury, or participant request to withdraw.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Sit-and-Reach Test (cm) | Immediately before and immediately after each intervention session | Lower-extremity flexibility was measured with a standard sit-and-reach box. Participants reached forward as far as possible with both hands while keeping the knees extended; the most distal point reached was recorded in centimeters. Higher values indicate greater flexibility. Safety Issue: No. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Y Balance Test (composite reach distance, cm) | Immediately before and immediately after each intervention session | Dynamic balance was assessed with the Y Balance Test. Participants reached as far as possible with the free leg in the anterior, posteromedial and posterolateral directions while balancing on the stance leg. Reach distances were summed and normalized to leg length; both lower extremities were tested separately. Higher values indicate better dynamic postural control. Safety Issue: No. |
| 30-Second Sit-to-Stand Test (number of repetitions) | Immediately before and immediately after each intervention session | Lower-extremity muscular endurance was assessed with the 30-second Sit-to-Stand Test using a standard chair without armrests. Participants performed as many full sit-to-stand repetitions as possible in 30 seconds with arms crossed over the chest. Higher values indicate greater lower-extremity endurance. Safety Issue: No. |
| Vertical Jump Height (cm) - My Jump Lab 2 | Immediately before and immediately after each intervention session | Counter-movement vertical jump height was measured with the validated My Jump Lab 2 smartphone application using a tripod-mounted iPhone (slow-motion video). Participants performed three maximal jumps with hands on the hips; maximum, minimum and mean jump heights were recorded. Higher values indicate greater lower-extremity power. Safety Issue: No. |
| Posture Analysis (PostureScreen Mobile - PSM) | Immediately before and immediately after each intervention session | Static posture was assessed using the PostureScreen Mobile (PSM) application with four-view photographs (anterior, posterior, right lateral, left lateral) taken with a tripod-mounted smartphone. Anterior translation of the head, shoulders and pelvis (sagittal plane) and lateral translations of the head, shoulders, pelvis and knees (frontal plane) were quantified by the application's computer-vision algorithm. Lower deviation values indicate better postural alignment. Safety Issue: No. |
Countries
Turkey (Türkiye)
Outcome results
None listed