Single Joint and Multi-Joint for More Muscle

One of the primary goals of our strength training should be to stimulate muscle hypertrophy (an increase in muscle mass).  More than simply improving our aesthetic appearance, muscle mass is a predictor of longevity and is now viewed as an endocrine organ as muscle secretes myokines (microscopic proteins that increase cross-talk between organ systems and drive health benefits).

When designing strength training programs, we can choose from two general types of exercises: multiple joint or single joint. 

Multiple joint exercises, as it sounds, involve articulation around more than one joint and involve multiple muscle groups.  A multiple joint exercise for the legs is leg press.

A single joint movement involves articulation around just one joint and usually involves just one muscle group.  A leg extension is a single joint exercise for the quadriceps. 

Traditionally, trainees, personal trainers, and coaches have prioritized multiple joint movements as they provided more bang for the buck. Meaning that one exercise stimulated multiple muscle groups. 

However, new research continues to support the inclusion of both single and multiple joint movements for building muscle. 

A brand-new study published in the Journal of Science and Sport in Exercise examined how our quadriceps (our frontal thigh musculature) hypertrophied in response to single and multiple joint exercises.

The researchers concluded that leg extensions stimulated more growth to the rectus femoris, the muscle toward the middle of the quadriceps.  Conversely, the leg press stimulated more growth to the vastus lateralis, the outer part of the quadriceps.  To optimize the development of our thighs, we should probably perform both. 

Take home message: Perform both single joint and multiple joint movements if your goal is to maximize muscle hypertrophy.