The benefits of aquatic plyometrics

Plyometric exercises performed in the water may offer similar training benefits to land-based plyometrics without the associated muscle soreness. That’s the encouraging conclusion of a US study of female volleyball players.

The established benefits of standard (land-based) plyometric training include improvements in strength, power, joint function, stability and running economy and a reduced incidence of serious knee injuries. Furthermore, numerous studies using jump-specific plyometrics have reported significant improvements in vertical jump performance.

However, plyometric training can also lead to acute muscle soreness and damage, and even injury, and is unsuitable for athletes undergoing rehabilitation after injury.

Some plyometric exercises can be performed in water, but so far only two good-quality studies have been carried out, with contradictory results.

The authors of the current study set out to compare the effects of aquatic plyometric training (APT) with those of flexibility exercises in 19 volleyball players who were also engaged in traditional pre-season volleyball training. Their theory was that APT would lead to greater enhancements in vertical jump (VJ) and muscular leg strength than flexibility exercises.

The volleyballers, selected from a local high school team, were randomly assigned to one of the following groups for six weeks:

• APT. A progressive programme, consisting of two 45-minute sessions in a swimming pool twice a week. The exercises included power skips, spike approaches, single- and double-leg bounding, continuous jumping for height, squat jumps with blocking form and depth jumps;
• Control. A whole-body flexibility programme performed twice a week, consisting of three sets of 8-10 static stretches for the major upper and lower body muscle groups.

Leg strength was tested at baseline and after six weeks and VJ was measured at baseline and after two, four and six weeks.

In terms of leg strength, the only difference between the groups was a significantly larger increase for the APT group in torque production in the non-dominant leg during maximal knee extension at 180°. Crucially, although the study did not specifically assess muscle soreness, there were no injuries, no complaints of significant muscle soreness and no dropouts from the APT programme.

The researchers concluded that: ‘APT could provide similar benefits to land-based plyometrics, but with lower risk of muscle soreness and/or overtraining’.

Med Sci Sports Exerc 2005; vol 37, no 10, pp1814-1819