The influence of incline walking on joint mechanics

•Incline treadmill walking significantly decreased internal knee abduction moment.•Negative relationship between the treadmill gradient and frontal-plane knee moment in 10% grade increments.

Walking is a popular form of exercise and is associated with many health benefits; however, frontal-plane knee joint loading brought about by a large internal knee-abduction moment and cyclic loading could lead to cartilage degeneration over time. Therefore, knee joint mechanics during an alternative walking exercise needs to be analyzed. The purpose of this study was to examine the lower-extremity joint mechanics in the frontal and sagittal planes during incline walking. Fifteen healthy males walked on a treadmill at five gradients (0%, 5%, 10%, 15%, and 20%) at 1.34 m/s, and lower-extremity joint mechanics in the frontal and sagittal planes were quantified. The peak internal knee-abduction moment significantly decreased from the level walking condition at all gradients except 5%. Also, a negative relationship between the internal knee-abduction moment and the treadmill gradient was found to exist in 10% increments (0-10%, 5-15%, and 10-20%). The decrease in the internal knee-abduction moment during incline walking could have positive effects on knee joint health such as potentially reducing cartilage degeneration of the knee joint, reducing pain, and decreasing the rate of development of medial tibiofemoral osteoarthritis. This would be beneficial for a knee surgery patient, obese persons, and older adults who are using incline walking for rehabilitation and exercise protocols. Findings from the current study can provide guidance for the development of rehabilitation and exercise prescriptions incorporating incline walking.