Effects of 8-Week TRX Suspension Training on Body Composition, Anaerobic Power, and Biomotor Abilities in Young Male Volleyball Players

Suspension training using TRX equipment leverages body weight and gravity to develop strength, balance, flexibility, and core stability simultaneously. In volleyball, explosive power, sprint acceleration, and lower-body strength are essential physical performance components. This study was designed as a randomized controlled field trial with a pre-test and post-test design to evaluate the effects of chronic TRX training in young athletes.

The study was conducted at Mus Spor High School indoor sports facility following ethical approval and parental/participant informed consent procedures compliant with the Declaration of Helsinki.

Both groups underwent initial baseline testing before the 8-week period and final post-testing immediately after the completion of the protocol.

Baseline and post-intervention assessments included:

Body Composition: Evaluated using bioelectrical impedance analysis (Tanita BC-418 MA) following standard pre-test dietary and activity controls (measuring body weight, BMI, body fat percentage, fat-free mass, and total body water).

10-Meter Sprint Performance: Assessed using wireless photocell timing gates with a standing start 50 cm behind the line (best of two trials recorded).

Vertical Jump: Measured via Bosco Ergojump mat with hands placed on hips to eliminate arm swing assistance (best of two attempts recorded).

Leg Strength: Evaluated using a standard leg dynamometer with knees bent and back straight (best of two trials recorded in kg).

Handgrip Strength: Evaluated using a handgrip dynamometer with the arm straight at a 45-degree angle from the body (best trial recorded in kg).

Anaerobic Power: Evaluated via the 30-second Wingate Anaerobic Test on a Monark 834 E bicycle ergometer with a braking load equivalent to 7.5% of the participant's body weight. Key parameters included Peak Power (W/kg), Mean Power (W/kg), Minimum Power (W/kg), and Fatigue Index (%).

Intervention Protocol:

The TRX group completed 16 structured training sessions over 8 weeks (2 sessions per week). Each 16-minute session consisted of 8 specific TRX exercise variations: TRX Squat, TRX Row, TRX Squat Jump, TRX Chest Press, TRX Lateral Jump Squat, TRX Biceps Curl, TRX Assisted Pistol Squat, and TRX Tricep Extension. Progression was maintained at 2 sets of 8 repetitions, with 24 seconds of work and 30 seconds of rest per exercise, and a 120-second rest interval between sets. The control group engaged only in standard volleyball coaching drills and match practice.

Inclusion criteria

• Being a male volleyball player aged between 14 and 18 years
• Active membership in the Mus Sports High School volleyball team
• Voluntary participation in the study with signed informed consent from both the participant and their parent/guardian
• Continuous participation in regular volleyball team practices
• No history of severe musculoskeletal injuries or surgeries in the lower or upper extremities in the past 6 months

Exclusion criteria

• Absence from more than 10% of the planned TRX or volleyball training sessions during the 8-week intervention period
• Occurrence of any acute injury or medical condition preventing participation in training or performance tests
• Simultaneous participation in any other structured resistance, plyometric, or high-intensity conditioning program outside of the study protocol
• Failure to perform pre- or post-intervention performance tests