1.
Biomechanical characteristics of adults walking in shallow water and on land.
Barela, AM, Stolf, SF, Duarte, M
Journal of electromyography and kinesiology : official journal of the International Society of Electrophysiological Kinesiology. 2006;(3):250-6
Abstract
Although water environment has been employed for different physical activities, there is little available information regarding the biomechanical characteristics of walking in shallow water. In the present study, we investigated the kinematics, ground reaction forces (GRF), and electromyographic (EMG) activation patterns of eight selected muscles of adults walking in shallow water and on land. Ten healthy adults were videotaped while walking at self-selected comfortable speeds on land and in water (at the Xiphoid process level). In both conditions there was a force plate embedded in the middle of each walkway to register the GRF components. Reflective markers were placed over main anatomical landmarks and they were digitalized later to obtain stride characteristics and joint angle information. In general, walking in water was different to walking on land in many aspects and these differences were attributed to the drag force, the apparent body weight reduction, and the lower comfortable speed during walking in shallow water. The joint range of motions (ROM) were not different, the segment ROM, magnitudes of GRF components, impact force, and impulse were different between the two conditions. The present results will contribute to a better understanding of this activity in the context of training and rehabilitation.
2.
Functional roles of lower-limb joint moments while walking in water.
Miyoshi, T, Shirota, T, Yamamoto, S, Nakazawa, K, Akai, M
Clinical biomechanics (Bristol, Avon). 2005;(2):194-201
Abstract
OBJECTIVE To clarify the functional roles of lower-limb joint moments and their contribution to support and propulsion tasks while walking in water compared with that on land. DESIGN Sixteen healthy, young subjects walked on land and in water at several different speeds with and without additional loads. BACKGROUND Walking in water is a major rehabilitation therapy for patients with orthopedic disorders. However, the functional role of lower-limb joint moments while walking in water is still unclear. METHODS Kinematics, electromyographic activities in biceps femoris and gluteus maximums, and ground reaction forces were measured under the following conditions: walking on land and in water at a self-determined pace, slow walking on land, and fast walking in water with or without additional loads (8 kg). The hip, knee, and ankle joint moments were calculated by inverse dynamics. RESULTS The contribution of the walking speed increased the hip extension moment, and the additional weight increased the ankle plantar flexion and knee extension moment. CONCLUSIONS The major functional role was different in each lower-limb joint muscle. That of the muscle group in the ankle is to support the body against gravity, and that of the muscle group involved in hip extension is to contribute to propulsion. In addition, walking in water not only reduced the joint moments but also completely changed the inter-joint coordination. RELEVANCE It is of value for clinicians to be aware that the greater the viscosity of water produces a greater load on the hip joint when fast walking in water.