The Investigations of Core Muscles, Gait, Balance and Proprioception in Transtibial Amputees

Position sense of the knee joints in both amputated and intact limbs will be measured using a dual digital inclinometer (ACUMAR™, Lafayette, USA). Participants are instructed and trained before testing. The participant was asked to lie prone with the knee positioned at 40 degrees. After learning this angle, the participant was asked to reproduce the remembered angle independently. The difference between the target angle and the reproduced angle was recorded. This procedure was repeated three times.

Position sense of the trunk will be measured using a dual digital inclinometer (ACUMAR™, Lafayette, USA). Tests are conducted barefoot on a firm surface with eyes closed. Participants are instructed and trained before testing. For trunk position sense, inclinometers are placed on T1 and S1 spinous processes, and participants perform 30-degree trunk flexion movements and then return to neutral, attempting to replicate the angle three times.

Core muscle function will be assessed by measuring transversus abdominis (TrA) muscle strength using the Stabilizer Pressure Biofeedback Unit (Chattanooga Group Inc, USA). Participants lie prone with pressure set at 70 mmHg and perform the abdominal drawing-in maneuver three times for 10 seconds each; the average pressure change is recorded.

Core muscle endurance will be evaluated through McGill's endurance tests including trunk flexor, trunk extensor, and lateral plank tests. The trunk flexor test involves maintaining a 55-degree flexion position until the participant can no longer hold it. For all tests, participants will be asked to maintain the position for as long as possible, and the duration will be recorded.

Core muscle endurance will be evaluated through McGill's endurance tests including trunk flexor, trunk extensor, and lateral plank tests. The trunk extensor test is performed prone with pelvis, hips, and knees stabilized; participants hold a horizontal position until failure. For all tests, participants will be asked to maintain the position for as long as possible, and the duration will be recorded.

Core muscle endurance will be evaluated through McGill's endurance tests including trunk flexor, trunk extensor, and lateral plank tests. The lateral plank test requires participants to maintain a side-lying plank position with the body aligned until loss of form or contact with the ground. For all tests, participants will be asked to maintain the position for as long as possible, and the duration will be recorded.

Static balance will be evaluated using the single-leg stance test. Participants are asked to stand unsupported on one leg while maintaining balance. The duration they can hold this position is measured with a stopwatch and recorded in seconds

Gait speed will be assessed using the 10-meter walk test. Participants start from a standing position and walk 10 meters at their comfortable walking speed. The time to complete the 10 meters is measured with a stopwatch.