Many rowers and coaches include jumpies and other plyometric activities into their program. Jumping can be a great alternative to weight training for developing power as you approach the racing season, it has the advantage of being done at much higher speed than squats or leg press and combined with on water strength rows it can save trips to the gym for those with limited training schedules. However, jumping can be very taxing and there are several precautions that should be taken before starting into a jump training program.
Plyometrics are a very high intensity form of training, placing substantial stress on the bones, joints, and connective tissue. While plyometrics can enhance an athlete’s speed, power and performance it also places them at a greater risk of injury than less intense training methods. Prior to starting a program there are several variables to consider so the training sessions are performed in a safe and effective manner.
Plyometrics can be performed indoors or outdoors. The landing surface should be able to absorb some of the shock of landing. Gymnastic or wrestling mats are good indoor surfaces as are the sprung wood floors found in many aerobics studios. Thick exercise mats will absorb too much impact, are unstable, and eliminate the stretch reflex needed for plyometrics. Exercise mats should be less that 15 cm thick. Outdoors, plyometrics are done on the grass or sand. Jumping on concrete or asphalt can lead to knee, ankle and hip problems and should be avoided.
One of the advantages of plyometric training is that it can be done almost anywhere with very little equipment. Most equipment that is needed can be made or bought at very little cost.
Plastic cones can be ordered from sporting goods catalogers and many sports stores. Several height cones are needed. Cone heights should range from 15-60 cm.
Steps or Stadium Stairs
Steps are a useful plyometrics tool as long as they are safe and of suitable material. Concrete steps should be avoided because the landing surface is too hard. The stairs should be deep enough to allow the athlete to easily place their whole foot on the step. The steps should be closed to prevent the toes from getting caught under a step.
Boxes can be constructed out of wood. A sturdy frame is covered with plywood. Several different box heights are recommended 15cm, 30 cm, 45 cm, and 60 cm are the most common heights. Boxes of 90-145 cm may be needed for advanced athletes. Angled boxes can be created for lateral jumps and drills. Boxes should be of solid construction with a non slip surface.
Medicine balls can be made of rubber, plastic, or leather. Leather balls should only be used indoors with a partner because they are less durable than rubber or plastic balls. Medicine ball typically range in weight from 0.5-15 kg. Several different weights towards the lower to middle of this range are sufficient for most programs. Medicine balls can be quite expensive. Individuals or institutions that are short on money can make medicine balls from old soccer, basketball, or volleyballs. Cut a small hole in the ball insert a funnel and fill the ball with sand to a desired weight. Patch the hole using a bicycle tire patch and some duct tape.
Hurdles should be adjustable and can be made of wood or pvc piping. Hurdles can also be made by placing a dowl or taping string between two cones. Hurdle heights can vary form 30-120 cm. The cross bar on the hurdle should readily fall when hit during a jump or hop.
Footware should provide a good grip, lateral support, ankle support and still allow the foot to move naturally. Cross trainers and court shoes are better than running shoes, which often lack adequate lateral support. If landings are done on a proper surface the cushioning provided by the shoe is not very important.
Shot puts, dumbells, kettlebells, and bars can all be used for throwing and increasing resistance while jumping. Weighted vests, with adjustable weights, are a good way to increase resistance without excessive low back strain.
Athletes should have an annual physical in which joint stability and strength are assessed. Any athlete with a history of spinal, shoulder, or lower limb injuries should be cautious when starting a plyometric programs. Strength or flexibility imbalances between the right and left side or between agonist and antagonistic muscle groups increases the likely hood of injury during plyometrics. Strength differences between the right and left side of the body of as little as 5% can increase the risk of injury 25 times. When returning from an injury the athlete should have full strength in the injured area prior to returning to a plyometrics program.
Large athletes, over 100 kg, need to be cautious when doing plyometrics. Large athletes are at a greater risk of developing injury due to the compressive forces on the joints experienced during landing. High volume and high intensity plyometrics should be avoided. Depth jumping from a height greater than 45 cm should be avoided completely.
Plyometrics is the link between strength and power. In order to take advantage of the stretch shortening cycle and make sure the plyometrics are done safely the athlete should achieve specific strength goals prior to starting plyometrics. The athlete should be able to squat at least their bodyweight for lower body plyometrics and bench press 0.75 times bodyweight for upper body plyometrics. Until these strength goals are met the training program should focus on developing strength. If plyometrics are done, limit them to single response double leg jumps.
In the next column we will look at designing a jump training program.