heavy weights less reps

Many triathletes lift relatively light weights for a high number of repetitions in a misguided attempt to build endurance. Avoid this mistake. Weight training with light weights is little more than entertainment. A cyclist averaging 90 rpm for a three hour ride will complete 16,200 repetitions. In that context, are we really going to improve our muscles’ aerobic system with a set of 20 or 30 repetitions? Absolutely not! Research consistently shows that a triathlete incorporating high repetition weight training into his/her program will not increase aerobic conditioning at all.To this end, using heavy weights is a necessity. To achieve the goals of a strength training program, the muscles must be overloaded by a heavy weight, not by fatigue from acid buildup generated during high repetition strength training. Build endurance in the pool, on your bike, and in your running shoes. Build strength in the weight room. The most effective type of strength training program for a triathlete incorporates a single, very high intensity set for each muscle group. This stimulates the desired strength increase without building huge muscles or using up too much time or energy that we need for swimming, cycling, and running. Strength training is an important supplement, but it is a supplement. Spending hours in the weight room won’t improve triathlon performance.I recommend that triathletes use extremely slow speed of movement during strength training. Ideally, the lifting phase should take 8 – 10 seconds and the lowering phase should take 4 – 5 seconds. Slow movements provide many benefits for an endurance athlete, such as:
Providing more sustained, longer duration muscular contraction
Reducing momentum, making the muscle work through the full range of motion
Reducing microtrauma, the tiny tears in the muscle that cause soreness
Reducing injuries during strength training by reducing power. Power = Force x Speed. Force increases strength; power injures. Keeping speed of movement slow optimizes both.
Selecting the correct weight to be used is critical. The weight must be heavy enough to overload the muscle’s ability to produce force, but light enough that perfect technique can be maintained. Each set should last between 40 and 80 seconds. With slow movements this will not produce a large number of repetitions, but duration of contraction is key, not number of repetitions. A set of 30 repetitions can amount to 20 seconds of muscular contraction, while a set and a set of 6 repetitions can amount to 90 seconds of contraction. Use your watch to monitor set volume. Using 12 to 15 second repetitions, each set will require only 4 or 5 repetitions. When you become strong enough that 80 seconds of continuous contraction are possible, increase the weight by about 5 percent. This will reduce the set duration back toward 40 seconds. Gradually build duration back up before increasing the weight again.