So anyone who’s been around a gym will have heard of the old split training method, where your training is divided into leg, back, chest and arm days. The idea is to overload one muscle group on one training day and then another the next and so on, allowing you to apply enough stress to elicit a hypertrophic (muscle building) response while still being able to train multiple days in a row. These sorts of programs also typically have a very high volume and tend to use single joint and small muscle mass, or ‘isolation’ exercises.
This works great for bodybuilders. They get bigger using this training method. The thing is, athletes aren’t bodybuilders.
Even athletes like prop forwards that require a lot of muscle bulk also need functionally strong, powerful, useful muscle, not just bulk for bulk’s sake. There’s no point carrying an extra 5kg than your opposition if that muscle doesn’t also contribute usefully to your speed and power generation on the field.
To get scientific for a moment, studies comparing muscle fibre type have found that bodybuilders have generated muscle hypertrophy of both Type I (‘slow twitch’) and Type II (‘fast twitch’) muscle fibres, whereas weightlifters and powerlifters have preferential hypertrophy of Type II muscle fibres. Weightlifters and powerlifters regularly train with loads of 90 – 100% 1RM (the max load that they can lift) and utilize periodised programs designed specifically to increase their maximal strength and power. Which just illustrates my point that there’s a difference between training for muscle size and training for muscle function.
Another issue to consider is that large muscle-mass, multi-joint exercises like barbell squats actually elicit a greater anabolic hormone (i.e. testosterone) response than small muscle mass, single joint exercises like leg curls. And Olympic lifts have been shown to produce some of the greatest hormonal responses of all resistance exercises. So not only are multi-joint exercises more functional to sporting movements, and therefore strength transfer will be greatest, but they will in fact give you a better hypertrophic response anyway.
So the question remains, who do you train like? Are you an athlete or a bodybuilder?