The present study aimed to compare the acute effects of cluster-set (CS) and traditional-set (TS) plyometric loading protocols on countermovement jump (CMJ) performance and reactive strength index (RSI-mod) in young tennis players. Twenty-eight male tennis players (age: 16.7 ± 1.3 years) were randomly assigned to either a CS or TS group. Following a familiarization session, participants completed an experimental session including pre-tests (CMJ and drop jump), a plyometric loading protocol (CS: 3 × \[5 × 2 repetitions, 15 s intra-set rest, 2 min between sets\]; TS: 3 × 10 repetitions, 3 min between sets), and post-tests at 15 s, 3 min, and 6 min. CMJ height and RSI-mod were assessed using the My Jump 2 application. Borg Scale, Total Quality Recovery (TQR) were apply after post-tests at 15 s, 3 min, and 6 min.
The present study aimed to compare the acute effects of cluster-set (CS) and traditional-set (TS) plyometric loading protocols on countermovement jump (CMJ) performance and reactive strength index (RSI-mod) in young tennis players. It was hypothesized that the CS method would elicit superior acute improvements in jump parameters and recovery due to reduced fatigue compared to the TS method. A total of 28 male adolescent tennis players, aged 13-17 years, voluntarily participated. Volunteers were randomly allocated into two experimental groups: Cluster Set Group (CS) and Traditional Set Group (TS). ). Participants were eligible if they met the following criteria. i. Engaged in tennis training for ≥2 years, with a frequency of ≥3 sessions/week and participation in ≥4 tournaments annually. ii. Had ≥6 months of experience with resistance and plyometric training. iii. No history of lower extremity muscle or joint injuries within the last three months. iv. No regular use of drugs or stimulants for at least six months prior to the study. The study consisted of two sessions: a familiarization session and an experimental session involving either the Cluster Set (CS) or Traditional Set (TS) protocol. Participants refrained from any exhaustive exercise for at least 48 hours prior to the familiarization session, and a 48-hour passive recovery period was observed between sessions. During the familiarization session, anthropometric measurements (height, body mass, body fat %) were recorded, and participants completed the Physical Activity Readiness Questionnaire (PAR-Q+). Following this, subjects performed a standardized warm-up and familiarization with the testing procedures. The experimental session included the following sequence: (i) Pre-test measurements: Countermovement Jump (CMJ) and Drop Jump (DJ), (ii) execution of either CS or TS plyometric protocol, (iii) immediate Post-15s): CMJ and DJ, (iv) passive recovery (3 min) followed by CMJ and DJ, and assessment using the Total Recovery Quality Scale (TQR), (v) additional passive recovery (3 m) followed by CMJ and DJ and TQR, (vi) final post-test (6 min): CMJ and DJ. Total workout 7 minutes and passive rest 6 minutes (Table 2). Participants were instructed to sleep at least 8 hours the night before testing. Maintain a normal diet and avoid medications, stimulants, ergogenic aids, or performance-enhancing substances. Before testing, all participants completed a 10-minute standardized warm-up, consisting of jogging, galloping, multidirectional running and jumping, calisthenic exercises for joint mobility, static and dynamic stretching. The procedure of the study is shown in Figure 1. All interventions were conducted between 15:00 and 17:00 in a synthetic-floored gym under controlled conditions (temperature: 18-24°C; humidity: 40-60%). Two Way ANOVA repeated measures analysis of variance, 2 groups (CS and TS) x 4 time (Pre, Post-15s; Post-3m and Post-6m) test was performed to compare the data and determine the differences. Bonferroni test was used for pairwise time and group comparisons.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
OTHER
Masking
NONE
Enrollment
28
Cluster Set: Vertical Jumping 3 set, 2 minute rest/set, in 1 set 5 x 2 repetition, 15 sec rest after each 2 repetition.
Traditional set: Vertical jumping 3 set, 3 minute rest / set, in 1 set 10 repetition/set
Bursa uludag University, Faculty of Sport Sciences
Bursa, Turkey (Türkiye)
Vertical Jump
The counter movement jump (CMJ) test was used to determine vertical jump height. CMJ is widely used to monitor neuromuscular status (i.e. fatigue, performance, strength, and muscle overcompensation) from the analysis of bilateral mechanics and the ability to generate and the ability to generate and absorb ground reaction forces by the lower extremity. The My Jump 2 (Copyright©Carlos Balsalobre Fernández) application of the My Jump Lab tools, based on artificial intelligence (AI) used to measure CMJ. An iPad Pro 11-inch Model Air M2 (Apple Inc. Cupertino, CA) used to capture each trial.
Time frame: From enrollment to the end of treatment at 15 days
Vertical Jump
The counter movement jump (CMJ) test was used to determine vertical jump high. The My Jump 2 (Copyright©Carlos Balsalobre Fernández) application of the My Jump Lab tools, based on artificial intelligence (AI) used to measure CMJ. An iPad Pro 11-inch Model Air M2 (Apple Inc. Cupertino, CA) used to capture each trial.
Time frame: From enrollment to the end of treatment at 15 days
Reactive Strength Index (RSI-mod)
The Drop Jump (DJ) test was used to determine the RSI-mod. The DJ can be used to determine the intensity of plyometric exercises, measure lower body reactive strength, monitor neuromuscular fatigue and test lower extremity stiffness. The DJ is a frequently analyzed metric for determining the RSI. It assesses an athlete's ability to rapidly transition from eccentric to concentric contraction and how much force the athlete can produce in the shortest possible time. There are multiple calculations available to measure the RSI-mod, but the most used is jump height (meters) ÷ ground contact time (seconds). Participants were asked to perform the DJ test by dropping to the ground from a 40 cm frame height with their hands on their hips and jumping upwards with maximal effort in the shortest time. Vertical jump distance and RSI were determined using the My Jump 2 app.
Time frame: From enrollment to the end of treatment at 15 days
Body composition
Participants' body weight and body fat percentage were assessed using a Tanita BC-418 bioelectrical impedance analyzer (Tanita Corp., Tokyo, Japan). Height was measured with a Seca stadiometer (Seca Instruments Ltd., Hamburg, Germany).
Time frame: From enrollment to the end of treatment at 15 days
Recovery
Recovery perception was evaluated using the Turkish version of the Total Quality Recovery (TQR) scale. This scale ranges from 6 points ("very poor recovery") to 20 points ("very good recovery"). Participants completed the TQR at the end of each 3-minute passive rest period following Post-15s and Post-3m jump tests.
Time frame: From enrollment to the end of treatment at 15 days
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