Athletic Performance
Conditions
Keywords
Microdosed Plyometric Training, Conventional Plyometric Training, Adolescent Basketball Players, Explosive Power, Speed, Agility, Reactive Strength, Jump Performance
Brief summary
This randomized controlled trial compared microdosed and conventional plyometric training in adolescent male basketball players. Forty participants aged 12-16 years were randomly assigned to either a microdosed training group or a conventional training group for 8 weeks. Both groups performed the same plyometric exercises and completed the same weekly training volume of 240 ground contacts. The microdosed group completed six sessions per week with 40 ground contacts per session, whereas the conventional group completed two sessions per week with 120 ground contacts per session. The study evaluated changes in jump performance, reactive strength, sprint performance, agility, and body composition. The study was completed before registration on ClinicalTrials.gov and is being registered retrospectively for transparency.
Detailed description
This study was an 8-week, assessor-blinded randomized controlled trial designed to compare the effects of microdosed and conventional plyometric training in adolescent male basketball players. Forty male basketball players aged 12-16 years were randomly allocated in a 1:1 ratio to a microdosed training group (MT, n=20) or a conventional training group (CT, n=20). Both groups continued their regular basketball training and performed the same plyometric exercises, including ankle hops, hurdle jumps, and drop jumps. The total weekly plyometric training volume was matched between groups. The MT group completed six sessions per week with 40 ground contacts per session, whereas the CT group completed two sessions per week with 120 ground contacts per session. Therefore, both groups completed 240 ground contacts per week and 1,920 ground contacts over the 8-week intervention. Exercise technique, hurdle height, box height, and recovery intervals were standardized between groups. Outcomes were assessed before and after the intervention. These included body mass, body fat percentage, countermovement jump height and concentric peak power, squat jump height and concentric peak power, eccentric utilization ratio, drop jump height, reactive strength index, three-quarter-court sprint time, and hexagon test completion time. This study was completed before registration on ClinicalTrials.gov. Therefore, this record represents a retrospective registration based on the completed study protocol and collected study data.
Interventions
The intervention lasted 8 weeks. Participants completed six sessions per week with 40 ground contacts per session. Each session included ankle hops (2 sets × 10 repetitions), hurdle jumps over 70-cm hurdles (3 sets × 5 repetitions), and drop jumps from a 50-cm box (5 repetitions). Participants rested for 30 seconds between sets of ankle hops and hurdle jumps and 15 seconds between drop-jump repetitions. The total weekly volume was 240 ground contacts.
OTHERConventional Plyometric Training
The intervention lasted 8 weeks. Participants completed two sessions per week with 120 ground contacts per session. Each session included ankle hops (6 sets × 10 repetitions), hurdle jumps over 70-cm hurdles (9 sets × 5 repetitions), and drop jumps from a 50-cm box (15 repetitions). Participants rested for 30 seconds between sets of ankle hops and hurdle jumps and 15 seconds between drop-jump repetitions. The total weekly volume was 240 ground contacts.
Sponsors
Chongqing Normal University
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
OTHER
Masking
SINGLE (Outcomes Assessor)
Masking description
Outcome assessors were blinded to group allocation.
Intervention model description
Participants were randomly assigned in a 1:1 ratio to either microdosed plyometric training or conventional plyometric training for 8 weeks.
Eligibility
Sex/Gender
MALE
Age
12 Years to 16 Years
Healthy volunteers
Yes
Inclusion criteria
* Male adolescent basketball players aged 12-16 years. * Regular participation in organized basketball training. * No lower-limb injury within the previous 3 months. * No systematic plyometric training within the previous 6 months.
Exclusion criteria
* Injury or illness that prevented continued participation in the study. * Participation in additional structured lower-limb training during the intervention. * Failure to complete either the PRE or POST assessments.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in Countermovement Jump Height | Baseline and immediately after the 8-week intervention | Countermovement jump height was assessed using two portable three-dimensional force plates sampling at 1,000 Hz. Participants performed three valid maximal countermovement jumps with 60 seconds of rest between trials. The trial with the greatest jump height was retained for analysis. Jump height was recorded in centimeters (cm). |
| Change in Countermovement Jump Concentric Peak Power | Baseline and immediately after the 8-week intervention | Countermovement jump concentric peak power was assessed using two portable three-dimensional force plates sampling at 1,000 Hz. Participants performed three valid maximal countermovement jumps with 60 seconds of rest between trials. Concentric peak power was recorded in watts (W). |
| Change in Squat Jump Height | Baseline and immediately after the 8-week intervention | Squat jump height was assessed using two portable three-dimensional force plates sampling at 1,000 Hz. Participants started from a stationary squat position with approximately 90 degrees of knee flexion and jumped vertically without a preparatory countermovement. Three valid trials were completed with 60 seconds of rest, and the trial with the greatest jump height was retained. Jump height was recorded in centimeters (cm). |
| Change in Squat Jump Concentric Peak Power | Baseline and immediately after the 8-week intervention | Squat jump concentric peak power was assessed using two portable three-dimensional force plates sampling at 1,000 Hz. Participants completed three valid squat jumps with 60 seconds of rest between trials. Concentric peak power was recorded in watts (W). |
| Change in Drop Jump Height | Baseline and immediately after the 8-week intervention | Drop jump height was assessed using two portable three-dimensional force plates sampling at 1,000 Hz. Participants stepped from a 50-cm box, landed on the force plates, and immediately performed a maximal vertical rebound jump while attempting to minimize ground-contact time. Three valid trials were completed with 60 seconds of rest. Jump height was recorded in centimeters (cm). |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Change in Reactive Strength Index | Baseline and immediately after the 8-week intervention | Reactive strength index was assessed during the drop jump test and calculated by dividing drop jump height in meters by ground-contact time in seconds. Three valid trials were completed, and the trial with the highest reactive strength index was retained for analysis. Reactive strength index was expressed in meters per second (m/s). |
| Change in Eccentric Utilization Ratio | Baseline and immediately after the 8-week intervention | The eccentric utilization ratio was calculated by dividing countermovement jump height by squat jump height. Higher values indicate a greater contribution of the stretch-shortening cycle to jump performance. |
| Change in Three-Quarter-Court Sprint Time | Baseline and immediately after the 8-week intervention | Three-quarter-court sprint performance was assessed over 22.86 meters using an electronic timing-gate system. Participants started from a stationary split stance 0.5 meters behind the starting line and sprinted maximally through the finish line. Three trials were completed with 3 minutes of rest, and the fastest time was retained. Sprint time was recorded in seconds (s). |
| Change in Hexagon Test Completion Time | Baseline and immediately after the 8-week intervention | Agility was assessed using the hexagon test. Participants completed three clockwise circuits by jumping with both feet across each side of a hexagon and returning to the center while maintaining the same body orientation. Three valid trials were completed with 2 minutes of rest, and the fastest completion time was retained. Time was recorded in seconds (s). |
| Change in Body Mass | Baseline and immediately after the 8-week intervention | Body mass was assessed using a multifrequency bioelectrical impedance analyzer (InBody 270). Participants were assessed barefoot and wearing light sports clothing after emptying their bladder. Body mass was recorded to the nearest 0.1 kilogram (kg). |
| Change in Body Fat Percentage | Baseline and immediately after the 8-week intervention | Body fat percentage was assessed using a multifrequency bioelectrical impedance analyzer (InBody 270). Participants were assessed barefoot and wearing light sports clothing after emptying their bladder. Body fat percentage was recorded to the nearest 0.1%. |
Countries
China
Contacts
PRINCIPAL_INVESTIGATORAo Xiang
Chongqing University of Education
Outcome results
None listed