The Effect of Therapeutic Exercise on Cartilage Morphology and Physical Function for Individuals at High Risk of Knee Osteoarthritis

Short echo T2*

Short echo time T2\* imaging is used to diagnose early cartilage degeneration. T2\* measures the rate at which the MRI signal decays, particularly focusing on short-T2 signals (less than 10 milliseconds) which decay rapidly (3-6).

Single leg hop test for a distance

The Single Leg Hop Test for distance is one of four assessments used to evaluate athletes' horizontal movement capabilities. These tests, collectively known as the 4 Single Leg Hop Tests, were established by Noyes et al (7). They include the Triple Hop for distance, the Single Leg Hop Test for distance, the 6-meter hop for time, and the Crossover Hop for distance. In the Single Leg Hop Test for distance, participants stand on one leg with their toes aligned along a designated landmark line. They then execute a forward hop, landing eccentrically while maintaining balance on the tested leg. The examiner measures the distance from the initial landmark line to the point where the participant's heel contacts the ground (8). This test is valuable for assessing lower extremity strength, power, and balance. It has been shown to be a reliable and valid measure for evaluating aspects of lower extremity function (9-10).

Single Leg Squat Test

The Single Leg Squat Test is a functional movement assessment used to evaluate lower extremity strength, neuromuscular control, and stability. Beyond its focus on lower limb function, it also helps identify core muscle strength and provides insights into an individual's capabilities in cutting, running, and landing (11). The SLST assesses the ability to alternate between concentric and eccentric contractions of the knee and hip muscles (12). In the test, the patient stands on one leg with their foot aligned with a straight line. The examiner assists with balance and ensures proper form. The patient then performs knee bends until the line along their toes is no longer visible, within a 30-degree range of knee flexion. Each patient has 30 seconds to complete as many repetitions as possible, with the maximum number recorded (13-16). The physiotherapist monitors and adjusts the test to maintain accuracy and consistency.

The Timed Stair Climbing Test (SCT)

The Timed Stair Climbing Test (SCT) is a functional performance assessment designed to evaluate lower extremity strength, endurance, and functional mobility. Participants will ascend and descend a 12-step staircase, with each step measuring 18 cm in height and 28 cm in depth. The objective is to complete the test as quickly as possible while ensuring a sense of safety and comfort. While the use of one handrail is optional, participants are encouraged to refrain from using it (17).

The Single Leg Chair Rise (SLCR) test

The Single Leg Chair Rise (SLCR) test evaluates quadriceps strength and can also help diagnose mid-lumbar nerve root impingement and radiculopathy (18,19). It has a sensitivity of 0.48, a specificity of 0.90, a positive likelihood ratio of 4.60, and a negative likelihood ratio of 0.58 (19). The protocol uses a 45.7 cm chair. Participants, dressed and shod, sit with arms crossed, the tested leg flexed at 90 degrees, and the other leg extended without touching the ground. They rise to full knee extension and then return to the seated position to complete one repetition. The test includes two assessments: one measuring endurance with as many repetitions as possible in 30 seconds, and another measuring power by completing five repetitions as quickly as possible. Each test is performed twice, with the best score recorded (20).