Contrast Loading

Contrast training is simple. Lift heavy then lift fast. This isn’t a new concept, but as you will see the applications are endless! The method involves alternating between heavy and light load exercises to improve muscular power by focusing on producing more force or velocity with your exercises. Both are accomplished by requiring you to perform two exercises back-to-back where the first exercise is a traditional strength exercise, and the second exercise is an explosive exercise, using the same muscles and movement patterns. Improvements can be noticed in not only the “main” bilateral strength lifts (deadlifts, squats, and bench press), but also improvements in jumps and sprint times for athletes. The heavy loading fires up the CNS and allows greater activation of the muscles when the subsequent lighter loading is completed. You will not only teach your body how to activate more muscle, but how to activate that muscle or groups of muscles more quickly (this is your rate of force development or RFD). Imagine what would happen if you attempted to life a half full buck of water, that you thought was completely full. The discrepancy between the amount of force you thought you needed and the the actual force required, would result in the bucket moving twice as fast as you intended.

The Benefits

The most obvious is the clear increase in power output due to improved rate of force development. When you do an explosive movement directly after you complete a heavy strength exercise, you are teaching your body to recruit more motor units for tasks like sprinting and jumping. For weight loss/body composition benefits, you can use the contract loading to increase the total amount of work you do by recruiting more motor units for high-speed body weight exercises. This is far more metabolically demanding that straight sets of these exercises would be. For muscle building, the obvious mechanism is the fact that you’re recruiting more motor units than normal, hence stimulating more muscle for growth.

The Research

Experts have claimed improved power gains by three times compared to conventional programmes. One study observed a 2.8% increase in jump height when athletes performed explosive jump-squats, after a set of relatively heavy resistance half-squats. It was suggested that preceding the jumps with the half squats resulting a potentiation of the muscles, allowing a faster and more forceful contraction. The response was particularly noticeable in the fast-twitch motor units. Another study found that following three maximal voluntary contractions (MVC’s) of the quads, counter-movement jump (CMJ) height increased 3.3%.

An Australian study analysed three different types of weight training on 11 female athletes. Athletes were required to perform half squats on a Smith Machine, with the down-positions knee angle set at 90deg and the intensity fixed at 3RM. Jump squats were then completed in the modified Smith Machine positioned over a force place. A light resistance of just 30% of the 1RM half-squat (or about 32% of the 3RM half-squat resistance) was used as the load primarily because it had been previously found to provide maximal mechanical power outputs. The three workouts were categorised as either ‘traditional’, ‘contrast’ or ‘complex’.

The ‘traditional’ workout protocol involved three sets of light-load exercise (the jump squats), then three sets of heavy-load work (half-squats). A traditional programme moves from explosive to heavier loads throughout the workout. The ‘complex’ workout protocol on the other hand involved all sets of the heavy-load half-squats being performed before the three sets of explosive jump squats. Finally, the ‘contrast’ session protocol involved a set of the heavy half-squats, alternated with a set of the lighter jump-squats until three sets of each exercise had been performed. Each type of workout was preceded by identical thorough warm-ups.

What were the results?

Jump-squats during the first set of jump-squatting were worse in the complex workout when compared to the traditional and contrast workouts. This may be attributable to the fatigue associated with three sets of heavy-load 3RM half-squats.

If the heavy-load work is extensive enough to induce significant muscular fatigue, it cannot facilitate explosive movements.

Summary

The key principals that need to be understood here is post activation potentiation (PAP). PAP is the explosive capability of a muscle that is enhanced after it’s been forced to perform maximal or near-maximal contraction.

The following mechanisms are involved in creating post action potentiation

• Increase motor unit recruitment (Using resistance training at a higher percentage of a 1RM should elicit higher threshold motor units)

• Enhances motor-unit synchronisation

• Greater input to the motor neurone

• Decreases in presynaptic inhibition

Or in more basic terms, the nervous systems supercharges itself by throwing more motor units (muscle fibres and the nerves that activate them) into the job, and by taking off the brakes that would ordinarily inhibit an expression of all-out power.