**7. Conclusion**

This chapter focused on muscle activity during exercises in water especially variations of gait (walking and running) and other activities of daily living. Descriptions on how to waterproof electrodes, placing the electrodes on the muscle of interest, and the verification of EMG collection in the water environment was then discussed. The authors also suggest that when the electrodes are waterproofed appropriately, EMG recording is not affected by water immersion. Namely, we can measure muscle activity correctly even in underwater condition without any artifact.

In summary of the reported characteristics of muscles activity during walking in water, TA and thigh muscles and ES tended to show higher activity than land-walking with self-selected pace. There was a lower activity than land-walking with Triceps Surae muscle, VL and abdominal muscle. Further, most muscles tended to decrease their activity when walking on treadmill apparatus, compared to land treadmill walking. During DWR the characteristics of muscle activity for the thigh, hip and trunk muscles show higher activity than walking in water and/or on land, whilst the muscle activity of Triceps Surae muscle decrease dramatically. From these

results the authors concluded that muscle activity would probably decrease in DWR, when compared to land treadmill running. In addition, the muscle activity modality can be changed significantly byusingdifferentflotationdevices.Inthe results ofthe comparisonbetween water exercise and land exercise, the muscle activity modality was affected by the physical qualities of water (buoyancy and water resistance). For example, horizontal movement in water tended to increase agonist muscle activity, hence vertical movement and horizontal- and verticalincluded-movement decreased agonist muscle activity. The water physical qualities would affectthe posture during exercise and resultin changes to muscle activity modality. The muscle activity characteristics in fundamental variations of water-walking vary its pattern resulting in unique movements, and the characteristics basically conform with exercise direction. Run‐ ninginwater,withfeettouchingthebottomoftheswimmingpool,generatedthehighestmuscle activity. Walking in water with knee up has the lowest intensity among variations of water exercise when exercising in self-selected moderate pace.

This chapter introduced research comparing the EMG of water-walking to land-walking. The results concluded that the shank and thigh muscle activity during water-walking was similar to that of land-walking. Identifying the water environment can simulate land-walking in respect to muscle activity even at slow speed. This reinforces the concept in water environment as a legitimate and effective exercise. In addition, the water environment provides increased safety with respect to falls. In summary, the water environment would be very beneficial especially not only for the physically fit but also for people wishing to regain the normal motion which may be difficult to achieve on normal land environment.
