1. Adductor longus activation during two hip adduction exercises
Chloe Long and Neil Light
University Of Chichester, West Sussex, UK
Muscle Activation: Isometric vs Dynamic
Various exercises are prescribed in the prevention and rehabilitation of adductor-related groin pain. Isometric adductor ball squeeze exercises are commonly incorporated into rehabilitation programmes or pre-activity preparation due to its versatile positioning and adaptability. Whereas the fairly new Copenhagen Adduction exercise (Serner et al. 2013) offers a more dynamic and challenging alternative. The adductor longus (AL) muscle is commonly indicated in adductor pathology, yet there is minimal literature examining adductor muscle activation during such exercises. Understanding variation in levels of AL activation during differing exercises, may inform exercise selection and becomes a key component in the prevention and treatment of injury.
RESULTS & DISCUSSION
Table.1. Average peak and mean (average) sEMG from repetitions.
Peak (mV)
Mean (mV)
% of peak values
Ball Squeeze
0.34 ±0.19
0.12 ±0.08
33.48 ±5.21
Copenhagen Adduction
0.25 ±0.09
0.07 ± 0.03
25.8 ±5.46
The ball squeeze exercise produced larger average AL activity than the Copenhagen adduction exercise (p <0.046). The ball squeeze exercise also demonstrated higher percentage of peak sEMG activity (33%) compared to the Copenhagen adduction exercise (26%). No statistically significant differences between peak sEMG values were observed.
The results suggest that AL activation is higher during an isometric ball squeeze when compared with the more dynamic Copenhagen adduction exercise. This may be related to varying angles of hip flexion and adduction resulting in differing muscle lengths, which have been shown to alter EMG activity levels (Delahunt et al., 2011). Whilst the Copenhagen adduction exercise is a more dynamic and biomechanically challenging exercise compared to adductor ball squeezes to, these findings suggest that AL activation is not increased with the added physical demand of the Copenhagen adduction.
METHODS
Nine healthy collegiate football players completed a number of repetitions of adductor ball squeezes (45° hip flexion) and Copenhagen adduction exercises, with surface electromyography (sEMG) measuring AL activity.
Fig. 4. Percentage of sEMG taken from peak values of all participants.
Fig. 1. Electrode placement to measure adductor longus
CONCLUSION
Adductor ball squeezes are safe, load adjustable and simple to instruct requiring no assistance and therefore remain ideally suited for pre-activation exercises prior to activity (prevention) and importantly during early phase loading post adductor related injury, where the Copenhagen adduction exercise is not indicated and may be more suitable in late stage rehabilitation (treatment).
Fig. 2. Ball squeeze at 45°hip flexion
REFERENCES
Delahunt, E., Kennelly, C., McEntee, B. L., Coughlan, G. F., & Green, B. S. (2011). The thigh adductor squeeze test; 45°of hip flexion as the optimal test position for eliciting adductor muscle activity and maximum pressure values. Manual Therapy, 16,
Serner, A., Jakobsen, M. D., Anderson, L. L., Holmich, P., Sundstrup, E., & Thorborg, K. (2013). EMG evaluation of hip adduction exercises for soccer players: implication for exercise selection in prevention and treatment of groin injuries. British Journal of Sports Medicine, 3, 1-8.
Fig. 3. The Copenhagen Adduction