New research suggests that athletes can boost muscle strength and power with less risk of injury by exercising in water. In issues 4 and 5 of SIB (November-December 2000), we explored the potential damage that can be done by plyometric exercises if they are not carried out properly. Cyclic loading patterns, high impact forces, deep-knee flexion and high rates of force development were all highlighted as potential contributory factors to injury in athletes participating in plyometric training drills. Although those earlier articles indicated that some high impact plyometric training drills could possibly cause injuries, they couldn’t overlook the fact that when practiced in a controlled environment with all the safety factors taken into consideration, plyometics could still help improve athletic performance in areas such as vertical jump performance, leg strength, power and proprioception, a view supported by the research community (1). Our conclusion then on plyometric training, based on the information presented in the articles, was “look before your leap”, though some readers may have felt the potential benefits were still outweighed by the risk of injury.
So has anything changed? Well, 18 months on and the research world may have come up with a viable and safer alternative to land-based plyometric training – namely, in the pool. A research team based in Ohio looked at earlier studies investigating the efficacy of water-based plyometric training drills and found that improvements in vertical jump performance were still possible and that there were no significant differences between land and water-based training methods (1). This is great news for anyone looking for a low-risk power-based training tool for themselves or their healthy athletes. But what about the athlete returning from injury who needs to slot back into the training programme as soon as possible? Most “high intensity”, land-based plyometric drills are out-of-bounds for athletes returning to fitness, but what if they do the drills in the pool? The Ohio-based team found that many healthcare professionals are using the pool during the rehabilitation of injuries and several publications are expounding the virtues of pool-based plyometics in sports injury rehab(1).
Here are the benefits
So what makes pool-based plyometics such an enticing alternative to more traditional training and rehab methods? Let’s look at the main points.
Buoyancy, first of all. When you are up to your neck in it (so to speak), your body will only be bearing about 8% of its weight. Research has shown that on dry land the musculoskeletal system is subjected to minimum impact forces of between 3-5 times bodyweight as a result of landing during plyometric drills such as depth jumps. Take a typical male weighing 70kg and perform the same land-based drill in a pool and you will have immediately reduced the impact forces associated with the exercise from between 210-350kg to just 35-57kg. Not bad if your knees are a bit on the dodgy side! You can change the intensity level simply by changing the level of the water. Drop the water level to around mid chest and the body bears approximately 35% of the weight, increasing to around 54% when the water level is waist high.
Water provides support for the athlete’s body as it moves downwards and resistance as the athlete explodes upwards. The water will also add resistance to lateral movements, thus increasing their work intensity, with the potential benefit of improved strength levels (a massive benefit for athletes attempting to get back to full fitness following an enforced layoff due to injury). Athletes and individuals immersed in water have a higher pain threshold and patients with lower-limb arthritis have shown significant improvements in proprioception and balance(1). OK, an athlete returning from surgery may not necessarily react in the same way as an arthritic patient, but it is not inconceivable that the benefits experienced in one group could be replicated in another. Athletes suffering from ACL injuries, a common problem associated with participation in jumping sports (especially for females) may find pool-based plyometric sessions to be a viable alternative. Research has found reduced joint swelling, increased strength levels and range of movement when athletes took part in pool-based rehab sessions.
Where to start
Pool-based plyometric training sessions would appear to be a safe and viable alternative training tool for athletes who want all the benefits that plyometric training has to offer without the possible risk of injury. So where should you begin when putting your programme together? Well, this training method is still in its infancy so there don’t appear to be any hard and fast rules. The team based at Ohio University suggest you adopt the same training principles as those on dry land (volume, intensity, jump height, frequency). Here’s a quick summary of the key points (which are covered more fully in SIB issues 4 and 5).
Warm-up and cool-down – Particularly important in relation to plyometics due to the high level of eccentric muscle contractions during plyometric activities. Intensity – Progress from low-intensity drills such as skipping, hopping and in-place jumping to more advanced activities such as depth jumps.
Volume – Measured by the number of foot contacts or jumps performed. Entry level 20-30 contacts, building up to around 40 contacts per session.
Frequency – Two to four days recovery is needed between sessions.
How to keep your head above water
Obviously not all land-based drills transfer readily to the pool, but with a little common sense and a few useful tips from our friends in Ohio you should have no problem creating suitable pool-based drills. Before we suggest a typical programme (see next page), here are the points to bear in mind when taking to the water.
Water resistance slows the speed of rotation and athletes may find it difficult to perform drills with more than 180 degrees of rotation.
Wear a swimsuit that conforms to the body (sorry, chaps, that means no more big baggy surf dude shorts, you’re gonna have to dust off your Speedo’s!). Too much material is going to create excessive drag and won’t help you achieve a rapid rebound.
Get some aquatic shoes with non-slip soles (available from several aquatic training catalogues). These will help ensure you achieve a good foot contact, reducing the likelihood of slipping and possible injuries. If your pool owner is feeling generous he may let you use some old trainers (just make sure you’ve not just completed a cross-country run in them!)
Run through the drills on dry land before getting into the water. If you are going to train as a group, make sure your athletes keep their distance to avoid creating a current. If your athletes create a strong current, others are going to be pulled along with minimal effort on their part, reducing the effectiveness of the session.
By following these guidelines pool-based plyometric training can be a useful training tool. As with most good ideas, there will always be an initial lack of evidence-based research to support its use and evaluate its effectiveness as a training tool. As coaches and athletes, we don’t always have the luxury of waiting for the men and women in white coats to deliver the research findings that we often need. Sometimes it’s a case of “suck it and see”. For what it’s worth, several athletes that I work with are currently completing pool-based plyometric training sessions similar to the example given overleaf.
Some athletes have ongoing injury problems while others are simply looking for a change to their routine that will offer a “low impact” alternative to plyometics without any loss in performance. Low-impact alternatives are especially important during heavy competitive phases of training when the athletes are pushing their bodies to the limit. So what’s the verdict? Well, at the moment the feedback has been excellent, especially from athletes with injuries who would ordinarily be twiddling their thumbs waiting to get back to full impact training. The more I see these sessions in use the more convinced I become of their effectiveness as an additional training tool in today’s modern conditioning programmes.
If you are still not convinced, then consider this, if nothing else, a trip to the pool will change the training environment and add some variety to an athlete’s training schedule. A happy and motivated athlete is probably going to train harder and recover faster than an athlete who is bored to tears with the same old routine.
Example: pool-based plyometric training programme
Training Goal: Develop and improve the production of muscle force and power.
Notes: Practice when focused and at a high degree of concentration (early in training). Complete a low-intensity dynamic warm-up before moving on to the plyometric exercises. Work with the water between waist-height and mid-chest. The more of your body that is out of the water, the greater the amount of impact. Wear aquatic shoes with non-slip soles to ensure proper contact, reducing the likelihood of slipping. Because plyometric drills involve maximal efforts to improve power production, complete and adequate recovery between repetitions and sets is required.
|Power skip||1||5 (L) 5 (R)||Perform one power skip and then rest for 5-10 seconds; repeat until you have completed all the repetitions. Once you have completed all 10 repetitions rest for 180 seconds before moving onto the next exercise.|
|Single leg lateral||1||5 (L) 5 (R)||Perform the lateral jumps over a barrier in a continuous motion jump over barrier (no rest between repetitions). Once you have completed all 10 repetitions rest for 180 seconds before moving onto the next exercise.|
|Explosive squat||1||10||Perform one explosive squat and then rest for 5-10 seconds, repeat until you have completed all the repetitions. Once you have completed all 10 repetitions rest for 180 seconds before moving onto the next exercise.|
|Split squat||1||10||Perform the split squat (cycle) in a continuous motion (no rest between repetitions). Once you have completed all 10 repetitions rest for 180 seconds before moving onto the next exercise.|
|Medicine ball chest pass||1||10||Perform one medicine ball chest pass and then rest for 5-10 seconds, repeat until you have completed all the repetitions. Once you have completed all 10 repetitions rest for 180 seconds before moving onto the next exercise.|
|Jump and reach||1||10||Perform one jump and reach and then rest for 5-10 seconds; repeat until you have completed all the repetitions. Once you have completed all 10 repetitions rest for 180 seconds before moving onto the next exercise.|
Reference: Miller, M.G., Berry, D.C., Gilders, R. & Bullard, S. Recommendations for implementing an aquatic plyometric programme. Strength and Conditioning Journal. Vol 23 No 6 28-35.