I'm posting the information below from one of Alwyn Cosgrove's recent blogs.
In some of my previous blogs, I talked about focusing on movement patterns and compound, multi-joint exercises to achieve a variety of fitness and fat loss goals. The information below reinforces what I said before. The study below proves that isolation exercises are not as beneficial compared to compound, multi-joint exercises.
All the talk about bodypart training versus full-body routines, isolation exercise versus compound exercise, etc. is based upon a fundamentally flawed concept: That hypertrophy is somehow completely regionally specific.
Here’s a study that examines this in a bit more detail:
Rogers et al.
The Effect of Supplemental Isolated Weight-Training Exercises on Upper-Arm Size and Upper-Body Strength
Human Performance Laboratory, Ball State University, Muncie, IN.NSCA Conference Abstract (2000)
The researchers compared the effects of a weight training program on 5RM strength and arm circumference and divided the subjects into two groups.
Group One performed four compound upper body exercises.
Group Two used the same program but included bicep curls and triceps extensions.
The results showed that both groups significantly increased strength and arm size. However, the addition of direct arm training to group two produced no additional effect on strength or arm circumference after 10 weeks of training.
The additional localized training did not result in anything that the bigger compound exercises didn’t provide.
Let me present a hypothetical example:
Twin brothers eating the same diet and working at the same job. Three times a week for the next 52 weeks: Both brothers undertake a progressive resistance training program – each adding weight, sets or reps in a logical manner over the whole year.
One difference: The first brother does deadlifts only. The second brother does arm curls only.
After a year, who do you think will be bigger overall? Including bigger arms? Obviously, it will be the first brother who put more overall stress and load through his system. Even though he didn’t bend his elbow at all.
Charles Poliquin is fond of quoting that in order to gain an inch on your arm, you’d have to gain 15lbs of muscle mass. If that’s true, it will happen a lot sooner with an exercise like the deadlift than it will with the dumbbell curl.
Bottom line is that muscle growth is a systemic issue not a localized one. If I put a stress on the forearm only it would grow, of course, but there would be a limit to that as the systemic load is small. But if you performed deadlifts, the systemic load would be so big that everything would grow.
And when we think about anabolics or anything that can enhance muscle growth, they are injected or consumed into the system. You don’t inject steroids in equal amounts into every muscle group. You don’t rub Surge or another post-workout recovery drink on your arms. Increased protein synthesis is a systemic phenomenon.
Therefore why not develop training strategies that target the entire system at once if fat loss or hypertrophy is what we want?