Harness Resistance Training: Does it Improve Jump and Enzymatic-Mechanical Muscle Performance in Young Soccer Players?

Background: Harness resistance training have been usedextensively by coaches and trainers in different sport, but iteffectiveness have to be proved.
Objective: Aim of this study was to explore the effects of an assisted harness resistance training program on vertical jump associated with squat and counter-movement jumps, biochemical fatigue markers (magnesium [Mg2+], lactate dehydrogenase [LDH],and creatine phosphokinase [CPK]), muscle displacement [Dm] and
contraction time [Tc]) in the lower limbs of young soccer players.
Methods: Eighteen young soccer players (age: 17.89 ± 0.98 years; height: 1.74 ± 0.07 m; body weight: 67.84 ± 7.26 kg; body fat percentage 12.02% ± 3.95%) were randomly assigned to three training groups: control, harness-assisted, and puller groups (three sessions per week for 8 weeks). Statistical significance was set at p< 0.05 for analysis of variances.
Results: No significant differences among the three groups in vertical jump regarding the squat jump (p=0.43) and countermovement jump (p=0.92); the biochemical fatigue markers CPK (p=0.38), LDH (p=0.51), or Mg2+ (p=0.79); or right rectus femoris (Tc: p=0.88; Dm: p=0.91), left rectus femoris (Tc: p=0.91; Dm: p=0.17),
right biceps femoris (Tc: p=0.20; Dm: p=0.06), left biceps femoris Tc: p= 0.17; Dm: p=0.63), right gastrocnemius lateralis (Tc: p=0.64; Dm: p=0.66), or left gastrocnemius lateralis (Tc: p=0.64; Dm: p=0.64).
Conclusion: The application of this kind of assisted sports training does not seem to effectively improve muscular power or enzymatic and muscle responses.