Int J Sports Med 2011; 32(5): 365-372
DOI: 10.1055/s-0031-1271678
Training & Testing

© Georg Thieme Verlag KG Stuttgart · New York

Effects of Jump Training with Negative versus Positive Loading on Jumping Mechanics

G. Markovic1 , S. Vuk2 , S. Jaric3
  • 1School of Kinesiology, Department of Kinesiology of Sport, University of Zagreb, Croatia
  • 2School of Kinesiology, Department of Kinesiology of Sport, Zagreb, Croatia
  • 3University of Delaware, Health, Nutrition, and Exercise Sciences, Newark, United States
Further Information

Publication History

accepted after revision December 30, 2010

Publication Date:
04 March 2011 (online)

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Abstract

We examined the effects of jump training with negative (−30% of the subject's body weight (BW)) vs. positive loading (+30% BW) on the mechanical behaviour of leg extensor muscles. 32 men were divided into control (CG), negative loading (NLG), or positive loading training group (PLG). Both training groups performed maximal effort countermovement jumps (CMJ) over a 7-week training period. The impact of training on the mechanical behaviour of leg extensor muscles was assessed through CMJ performed with external loads ranging from −30% BW to +30% BW. Both training groups showed significant (P≤0.013) increase in BW CMJ height (NLG: 9%, effect size (ES)=0.85, vs. PLG: 3.4%, ES=0.31), peak jumping velocity (v peak ; NLG: 4.1%; ES=0.80, P=0.011, vs. PLG: 1.4%, ES=0.24; P=0.017), and depth of the countermovement (Δh ecc ; NLG: 20%; ES=−1.64, P=0.004, vs. PLG: 11.4%; ES=−0.86, P=0.015). Although the increase in both the v peak and Δh ecc were expected to reduce the recorded ground reaction force, the indices of force- and power-production characteristics of CMJ remained unchanged. Finally, NLG (but not PLG) suggested load-specific improvement in the movement kinematic and kinetic patterns. Overall, the observed results revealed a rather novel finding regarding the effectiveness of negative loading in enhancing CMJ performance which could be of potential importance for further development of routine training protocols. Although the involved biomechanical and neuromuscular mechanisms need further exploration, the improved performance could be partly based on an altered jumping pattern that utilizes an enhanced ability of leg extensors to provide kinetic and power output during the concentric jump phase.

References

Correspondence

Dr. Goran Markovic

School of Kinesiology

University of Zagreb

Department of Kinesiology of

Sport

Horvacanski zavoj 15

10000 Zagreb

Croatia

Phone: +385/1/3658 606

Fax: +385/1/3634 146

Email: gmarkov@kif.hr