Compound interest pays
off in exercise

Sgt Bridget Pearce analysing a staff cadet's squatting technique at the RMC gymnasium. Photo by Cpl Wade Laube

Unfortunately there is still much misinformation and misunderstanding regarding the use of isolated exercises.

Many still consider, for example, that leg extensions will shape and tone the legs more than squats or leg pressing… unfortunately this misinformation is as technically accurate as those "'do this arm program and have 20inch biceps in two days" protocols.

It is still a common belief that compound exercises like squats will add bulk to the legs whilst isolation exercises, like leg extensions, will shape them.

This would mean that the muscles that create the movement of extension of the knee (ie, the quadriceps) would be able to tell the difference in the exercises and therefore decide to respond differently.

This is not the case. The quadriceps are responsible for knee extension … period. Whether the knee is extending for a leg extension in a leg extension or the leg press, squat, lunge, step up with other muscles in a compound action, is irrelevant, the muscles contract in the same way to complete their action.

The difference is that the compound exercises utilise other muscles which likewise adapt. Therefore with compound exercises more muscles adapt and therefore greater development, based on your training protocols, can be achieved. With isolation exercises, by utilising fewer muscles, you do not achieve the same total volume of muscle worked.

Furthermore, with the 'toned look' actually a combination of decreased body fat and increased lean muscle tissue, the compound exercises, by utilising more muscles, utilise more calories to perform the action and hence are more conducive to inducing the 'toned look' and shaping than the isolated exercises.

Isolated muscles also tend to develop lactic acid sooner and lactic acid actually prevents the muscle from 'burning fat' for energy.

So if you want to shape the muscles and 'chisel the body', utilise compound exercises.

Not only will you improve the 'tone'/shape of your muscles but you will also be training the muscles to work together more effectively (synergy) and thus improve neuromuscular (mind - muscle) function.

So forget those side leg raises and Pec Decs, use more joints at once and train for gain.

Note: If performing isolated actions for physiotherputic/injury prevention/rehabilitation reasons, fear not.

The physios are doing this to return the muscle to its correct function prior to reintegrating it into compound/complex movements.