Effects of Ball Mass on Plyometric Throwing Exercise Intensity

Document Type

Article

Publication Date

2014

Publication Title

Medicine & Science in Sports & Exercise Supplemental

DOI

10.1249/01.mss.0000493999.92315.8f

ISSN

1530-0315

Abstract

Despite the popularity of overhand plyometric throwing exercise, quantitative data regarding the intensity have not been reported. The effects of ball mass on exercise intensity have not been studied.

PURPOSE: To quantify overhand plyometric throwing intensity between various mass medicine balls and sexes via amortization time (AT) and ball contact (BC) and release (BR) momentum.

METHODS: Following a 5min moderate intensity arm ergometer warm-up, thirty-four healthy, college-aged adults, 17 men (1.70±.05m, 85.6±12.0kg) and 17 women, (1.65±.04m, 70.6±8.6kg) with overhand throwing experience completed eight repetitions of 90°/90° plyometric throws against an angled trampoline with four different (.115m diameter) mass medicine balls (1.0 kg, 1.5 kg. 2.0 kg, 2.5 kg). An electromagnetic tracking system (MotionMonitor, IST, Inc.) collected dominant arm kinematics. Hand kinematic data immediately following BC and prior to BR were considered to represent ball displacement. AT (time between BC and initiation of anterior ball displacement) and three dimensional ball momentum (resultant ball velocity × mass) were averaged across five trials.

RESULTS: No significant (P>.05) sex related differences were revealed. AT for the 2.5kg was significantly longer than 1kg (95% CIdiff: .015 to .055s) and 1.5kg (95% CIdiff: .008 to .053s). AT for 2.0kg was statistically equal to the other balls. Ball momentum was significantly greater at BR (end of concentric phase) compared to BR (beginning of eccentric phase) (95% CIdiff: 1.99 to 2.80m·s-1·kg). Ball momentum increased significantly (P<.001, range: 1.38 to 1.52 m·s-1·kg), in a linear manner (P<.001, η2=.947), with each ball mass progression.

CONCLUSIONS: AT, which represents the plyometric nature of the exercise, was statistically equal between the 1kg, 1.5kg and 2kg. Because contact with the trampoline was associated with a 37.7% decrease in ball momentum across all ball masses, the exercise intensity (represented by ball momentum), of the eccentric phases were less than the concentric phases. Relative to the 1kg, each additional .5kg ball mass was associated with a 50% increase in exercise intensity. For performance enhancement, we recommend the 2kg ball because it maximizes exercise intensity without prolonging the stretch shortening cycle.

Comments

© 2014 American College of Sports Medicine

Link to Full Text

Share

COinS