This study aims to investigate the differential effects of three training protocols: traditional Yo-Yo intermittent training, ball-dribbled Yo-Yo intermittent training, and small-sided games (SSGs) on aerobic capacity, anaerobic and exercise enjoyment in adolescent soccer players.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
SINGLE
Enrollment
42
Yo-Yo running training is a form of running-based high-intensity interval training characterized by repeated bouts of shuttle running with intermittent recovery periods. The training involves forward and backward running over a fixed distance at progressively increasing speeds, following standardized Yo-Yo test protocols.
Ball-dribbled Yo-Yo training is a modified form of Yo-Yo-based running training that integrates ball dribbling into an intermittent shuttle running format. This intervention combines repeated high-intensity running bouts with soccer-specific technical demands, requiring participants to control and dribble a ball while performing forward and backward shuttle runs at prescribed speeds.
Football court, Yuet Wah College
Macao, Macau
UM Kinesiology Lab
Macao, Macau
Yo-Yo Intermittent Recovery 1 test distance
Participants performed repeated 20-m shuttle runs between two lines at progressively increasing speeds dictated by standardized audio signals, interspersed with 10-s active recovery periods. The initial running speed was set at 10 km·h-¹ and increased stepwise according to the YYIR1 protocol. Participants were required to reach the 20-m line in time with the audio cue. A first failure to meet the line in time resulted in a warning, and the test was terminated after a second failure. The total distance covered before test termination was recorded as the YYIR1 score. YYIR1 distance is expressed in meters, with higher values indicating greater intermittent aerobic capacity and a superior ability to perform and recover from repeated high-intensity running efforts.
Time frame: Baseline and end of intervention at 4 weeks
Anaerobic power
Anaerobic power was assessed using the Wingate Anaerobic Test (WAnT) performed on a cycle ergometer. After a standardized warm-up, participants completed a 30-s all-out sprint against a resistance equivalent to 7.5% of their body mass. Participants were instructed to pedal as fast as possible throughout the entire test, and strong verbal encouragement was provided. Power output was recorded continuously. Peak power output (PPO) was defined as the highest mechanical power achieved over any 5-s interval, and mean power output (MPO) was calculated as the average power across the full 30-s test duration. Anaerobic power outcomes are expressed in watts (W), with higher PPO and MPO values indicating greater maximal and sustained anaerobic power capacity.
Time frame: baseline and end of intervention at 4 weeks
Physical activity enjoyment
Overall session enjoyment was assessed using the PACES-8. Participants rated how they felt about the activity on eight items using a 7-point Likert scale from 1 (unpleasurable) to 7 (pleasurable).Total scores ranged from 8 to 56, with higher scores indicating greater physical activity enjoyment.
Time frame: every Saturday acute after training during 4-week intervention
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Small-sided games (SSG) are a game-based soccer training intervention characterized by modified match play involving a reduced number of players on a smaller pitch. This intervention requires participants to engage in intermittent, high-intensity activities while performing soccer-specific technical and tactical actions under game-like conditions.
Repeated Sprint Ability
Repeated sprint ability (RSA) was assessed using a 6 × 40 m shuttle sprint test (20 m + 20 m with a 180° change of direction), with 20 s of passive recovery between sprints. Sprint times were recorded using infrared timing gates positioned at the start and finish lines. The primary RSA outcomes included best sprint time (RSA\_best), mean sprint time (RSA\_mean), and performance decrement (RSA\_dec). RSA\_best represents the fastest single sprint time and reflects maximal sprint capacity. RSA\_mean is the average time across all six sprints and reflects repeated-sprint performance.
Time frame: baseline and end of intervention at 4 weeks
10/30m sprint performance
Sprint performance was assessed using 10 m and 30 m linear sprint tests to evaluate acceleration and maximal running speed, respectively. Participants performed three maximal-effort trials over each distance on synthetic turf. Sprint times were recorded using infrared timing gates positioned at 0 m, 10 m, and 30 m. The primary outcomes were best sprint time and mean sprint time for both distances. The 10 m sprint reflects initial acceleration capacity, whereas the 30 m sprint reflects near-maximal sprint speed. Lower sprint times indicate better sprint performance.
Time frame: baseline and end of intervention at 4 weeks