Back in 2001 I started to put players with chronic knee injuries in the pool for 'pool based plyometric' sessions. They were load compromised so couldn't sustain high loads on land so I wondered if we could maintain (or even improve) performances if we unloaded them in the pool. Lots of coaches scoffed at the idea. How could this environment bring about any improvements in strength and power. How dare I call it plyometric. Well, my gut told me it was a good idea so I stuck with it and I know from the feedback and fitness data I have that it's a useful tool.
10 years down the line and my colleague Mark Jarvis sent me a recent review article that finally backs up what I was saying, almost 10 years on!!!!
'Our literature review found four studies that applied aquatic-based PLY. Martel et al.[163 reported a relative improvement in CMJA performance by +7.5% following 6-weeks of PLY conducted in 1.2mof deep water. In addition, the authors observed a relative increase in knee extensor strength at high velocities (+9.6-26.5%), but also a relative decrease in knee flexor strength and knee extensor strength at low velocities (from -9% to -3.4%). Stemm and Jacobson compared the effects of land-based and aquatic-based (knee-level water) PLY on vertical jump performance with identical PLY exercises performed by both groups. The aquatic-based group improved CMJA performance by +5.0% and the magnitude of improvement was similar to that achieved by the land-based PLYgroup. Furthermore, Robinson et al. reported large relative increases in vertical jump performance (+33.5%), sprint performance (+6.7%) and concentric and eccentric knee extensor/flexor muscle strength (+25-52%) in an aquatic-based group, and the magnitude of improvements was not significantly different from the land-based group. As expected, the reported muscle soreness was significantly higher in the land-based group. Finally, Miller et al. reported a small relative increase in vertical jump performance (+1.6%) and muscle power (+4.3%), with no relative changes in knee extensor/flexor muscle strength following 8 weeks of aquatic PLY.'