Differences Between The Bilateral And Unilateral Battle Rope Exercises In Joint Forces And Muscle Activation

Battle ropes are used as a workout to strengthen the upper body but it also requires lower body stability during the exercise. It is unknown how lower body joints and musculature are affected during this exercise in the inexperienced population. PURPOSE: To examine the muscle activation in the quadriceps and hamstring muscle groups along with the lower body frontal plane joint forces when performing the battle rope exercises unilaterally and bilaterally. METHODS: Maximal volumetric isometric contraction (MVIC) tests for the quadricep (Vastus medialis and vastus laterals) and hamstring (Semitendinosus and bicep femoris) muscle groups were conducted. Seventeen participants (20.3 ± 2.2-years) performed four bilateral and four unilateral battle rope trials of twenty seconds with three minutes of rest in between. Linear force in the medial-lateral direction on the right leg in the hip, knee, and ankle joints, ground reaction force (GRF) produced on the right side and muscle activation created during the bilateral and unilateral battle rope exercise were assessed using Bertec force plates, Qualisys motion capture, and Delsys electromyography systems. Peak muscle activations (reported in %MVIC) and forces (Newtons) were assessed during the down phase on the dominant limb side. RESULTS: There were significant increases in muscle activation during the bilateral compared to the unilateral exercise in the vastus lateralis (20.2 ± 11.7% vs 14.7 ± 7.2%, p = 0.002), vastus medialis (16.5 ± 11.4% vs 13.0 ± 9.0%, p = 0.002), semitendinosus (14.3 ± 11.6% vs 11.0 ± 10.3%, p = .002), and biceps femoris (12.8 ± 9.1% vs 9.8 ± 8.7%. p = 0.025). There were significant increases in laterally-directed ankle joint force during the bilateral compared to the unilateral exercise, in the right ankle (93.7 ± 66.1 N vs 76.5 ± 49.0 N, p = 0.04) and medially-directed GRF (103.5 ± 38.3 N vs 85.7 ± 25.2 N, p = 0.011) but no significant difference in the right hip (p = .326) and knee (p = .179) joint forces. CONCLUSION: When performing the bilateral battle rope exercise there is more lateral ankle joint force production and greater peak muscle activation being produced. The increase in medial GRF production during the bilateral exercise predominantly affects ankle joint force while causing an increase in muscle activation helping the body to stay balanced.