engleski

Optimal load for power production in vertical jumping

Introduction: Muscle power is considered one of the main determinants of athletic performance that requires explosive force production such as jumping (Kawamori and Haff, 2004). There has been an increasing volume of research focused on the load that elicits maximum power output. The mechanical output in isolated and complex movements depends on applied external load. The most of the studies in this area have investigated maximal power output in vertical jumping (VJ). In this work, we reviewed the results of all published studies that examined the effects of loading on mechanical output in VJ, with particular reference to training level of the tested subjects. Methods: A computerized search of articles that studied the effects of the loading on mechanical power output during VJ was performed using MEDLINE and SCOPUS databases. Results: From a total of 19 studies that examined the load-power relationship in VJ, the vast majority of authors reported that either an exceptionally small or zero external load (13 out of 19 studies) represents the optimal load for power production in VJ. Conversely, only six studies reported the optimal loads that were considerably higher than subjects’ body weight. It should be also noted that most of the reviewed studies revealed a loading associated decrease in power output (Jaric and Markovic, 2009). Discussion: This review of literature showed that about 70% of all included studies reported either body weight or the smallest external load applied as optimal for power production in VJ. It should be noted that these studies mainly used untrained individuals as subjects. In contrast, in about 30% of studies that revealed considerably higher external loads as optimal for power production in VJ, the authors used strength/power athletes as subjects. Besides the training level of subjects (Cronin and Sleivert, 2005), several other factors could be responsible for the observed discrepancy in optimal loading for power production in VJ. These include: 1) differences in data collection and analyses protocols (Dugan et al., 2004), 2) inclusion or exclusion of body weight in calculations of power, 3) determination of the loading and data collecting equipment (Crewther et al., 2005), and 4) use of free weights vs. machines (Dugan et al., 2004). In conclusion, this review showed that optimal load for power production in VJ appears to be the subject’s body weight. In contrast, strength/power trained athletes produce maximal power in VJ when using external loads ranging from 20% to 70% of their 1 RM in back squat.

muscle power; vertical jumping; optimal load

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