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This study was designed to examine the effects of proprioceptive neuromuscular facilitation (PNF) and weight training (WT) on muscular strength and athletic performance. Thirty college women were randomly assigned to one of three groups: WT, PNF, and control. WT and PNF subjects trained 3 days a week for 8 weeks. All subjects were tested for changes in knee and elbow extensor strength, throwing distance, and vertical jump. The WT group increased strength by 19.3% for knee extension and 20.4% for elbow extension while the PNF group increaseil22.1 and 29.1 %, respectively. PNF also increased throwing distance by 25% and vertical jump by 16% while WT had increases of 12.8 and 9.9% respectively. These findings indicate PNF might be superior to WT in athletic performance enhancement and, therefore, the better modality for athletic conditioning and injury rehabilitation. J Orthop Sports Phys Ther 1986;7(5):250-253.

Experiments using rapid-positioning movements in humans, where the subject is suddenly and unexpectedly provided with a change in the load characteristics of the limb, are described. Taken together, the pattern of results supports a mass-spring model of unidirectional limb action, where the limb moves to a position defined by the relative tensions in the agonist and antagonist. As well, various results provide evidence contrary to predictions from an impulse-timing viewpoint, where the motor program times the onset of impulses to the musculature, and against a feedback-processing viewpoint, where limb position is defined by minimizing positioning error indicated by feedback. The evidence suggests that the role of phasing in motor programs may be different for unidirectional actions on the one band and multi-directional and/or multi-component actions on the other.

In brief The six collegiate male volleyball players in this study had moderate aerobic capacity (56 ml·kg·min) and predominantly fast twitch fiber distribution (57%) in the vastus lateralis muscle. Prolonged volleyball play resulted in a greater depletion of glycogen in slow twitch fibers than in fast twitch and no hint of anaerobic fatigue. These results suggest that in spite of the apparent explosive activity of volleyball, the overall intensity is probably mild to moderate and therefore aerobic endurance may be critical to performance.