2.1. Design and Participants 
knee injury, pain, knee muscle strength and knee muscle, knee pain, trauma
HAND OSTEOARTHRITIS, SECONDARY
A double-blind, quasi-randomized trial was conducted in the hospital settings of Kasturba Medical college, Mangalore, between March 2021 and March 2022. The primary outcomes were measured using the pain scale and assessed using the visual analogue scale (VAS). The functional outcomes were measured using the knee injury and osteoarthritis outcome score (KOOS) and the secondary outcomes were knee muscle strength and knee muscle range of motion (ROM). A total sample size of 48 was included and a standard deviation of 0.74 was acquired from a previous study at a confidence level of 95% and precision d = 0.86 [Participants were randomly allocated by the referring surgeon using a random number table, and subjects were randomly allocated using the non-purposive sampling technique in one of the routinely followed and prescribed treatment groups, i.e., group (1) was the exercise therapy group, group (2) the collagen supplementation group, and group (3) underwent a combined intervention of exercise therapy and collagen supplementation (The inclusion criteria were as follows: (a) athletes above the age of 18 and below 55; (b) knee pain and stiffness that interferes with sports performance; (c) grades I and II on the Kellgren Lawrence scale, as diagnosed and confirmed by an orthopedician. The participants were screened based on the study’s eligibility requirements. The participants were excluded if they had any recent trauma or injury to the knee or any surgery in the past 3 months. 