In recent years, there has been a growing emphasis on gaining strength to enhance sports performance and prevent injuries. However, one crucial aspect that has received less attention is the importance of muscle symmetry between limbs. Various studies have demonstrated that being asymmetrical can lead to problems ranging from ACL injuries to falls in the elderly.

Muscle imbalances between limbs can occur due to various reasons, including previous injury, asymmetrical biomechanics, sport-specific training, or genetics. Unfortunately, many athletes may not even be aware of these imbalances, and they can go unnoticed for years until an injury occurs. As a physiotherapist, I often assess the reason for an injury, and side-to-side strength or neuromuscular differences can be a contributing factor.

The good news is that there are ways to self-assess muscle imbalances. Exercises that isolate a small amount of muscles, such as single-leg calf raises, single-leg bridges, single-leg knee extensions, single-arm chest press, and single-arm shoulder external rotation, can be used to assess strength or strength-endurance. You can also perform a single-limb exercise on one side, score the perceived effort out of 10, and compare it to the other side to assess differences.

Technology can also play a vital role in assessing side-to-side differences. Companies such as VALD offer easy-to-use equipment and interpretable data that allow athletes and professionals to quickly assess imbalances. For example, the VALD Force Decks can be used during a bridging activity to assess and correct asymmetry between limbs.

Video: ACU Researcher Ryan Timmins assesses bridging symmetry using VALD Force Decks. Video Credit: Learn.Physio, an online education platform for physiotherapists and health professionals 

If an asymmetry is detected, the next step is to address it. My approach is three-fold: isolate the weak muscle or functional movement pattern with a single-limb exercise/activity that addresses the deficiency, repeat the test until symmetry has been restored, and graduate exercises and activities back to normal bilateral movements. Restoring symmetry is not always a one-time fix and may require ongoing maintenance.

 Step Up Mick Hughes

Photo: Sports & Exercise Physiotherapist Mick Hughes using a single leg step up exercise to address quadriceps weakness

To prevent muscle imbalances, it is essential to have a mixture of both double-limb and single-limb exercises. Pay particular attention to differences between sides with single-limb activities, and if you feel an imbalance, get it checked out by a professional right away.

Preventing injuries and optimising sports performance involves more than just building strength. Muscle symmetry between limbs is an important aspect that should not be overlooked. By self-assessing, using technology, and addressing any asymmetries found, athletes can stay healthy and improve their performance. Remember, prevention is always better than cure.