All you need are the big compound lifts to build muscle, right? Not so fast. Science tells us that this is a myth. Muscle size requires more than just the compound lifts. You need to isolate certain muscles to get them to grow.
For instance, different parts of the hamstring complex can be regionally targeted through exercise selection. This falsifies the common belief that just sticking to the big lifts will give you a fully comprehensive training stimulus for building muscle.
Researchers investigated the muscle activity of the hamstrings during the leg curl, good morning, glute-ham raise, and Romanian deadlift (RDL) and found that hamstring activity was maximized in the RDL and glute-ham raise.
Another study compared hamstring exercises where movement originates at the hip versus the knee to see whether they'd cause differential activation of the hamstring muscle complex (1). The researchers found that the lying leg curl (where movement originates at the knee joint) elicited more activation of the lower lateral and lower medial hamstrings compared to the stiff-legged deadlift (where movement originates at the hip joint).
Their results were confirmed in another study, which concluded that people trying to maximize the involvement of the hams should consider focusing on both the glute-ham raise and RDL (2).
One Hip Joint Exercise, One Knee Joint Exercise
So if you think your hammies suck, maybe you're just not hitting them from all angles. Complete hamstring training should have at least one exercise where movement is focused at the hip joint, like the Romanian deadlift or its variations; and one exercise where movement is focused at the knee joint, like the leg curl, glute-ham raise or other isolation exercises.
And this goes for all muscle groups. Isolation exercises used on the same area (quads, biceps, glutes, delts) can have unique training benefits and impact muscle growth differently.
- Schoenfeld BJ, et al. Regional Differences in Muscle Activation During Hamstrings Exercise. J Strength Cond Res. 2014 Jun 24.
- McAllister MJ, et al. Muscle activation during various hamstring exercises. J Strength Cond Res. 2014 Jun;28(6):1573-80.