Can knee muscle activation be altered using modified clinical exercises in patients with osteoarthritis?

Participants will need to complete a series of clinical exercises. Participants will be given specific instruction on how to perform each of the following exercises; heel raise, wall squat, straight leg raise and step up. This will allow participants time to become familiar with the exercise. Participants will perform a total of 4 exercises with 2 variations being assessed (Normal exercise/ Modified exercise). 1 set of 10 repetitions will be performed with 2minutes rest between each exercise. The participants will perform the activity with little instruction during the normal exercise, then repeat the exercise with specific modifications to you if this changes muscle activation. All exercises will only be performed on one occasion. Performing the calf raise (CR) will require the participant to stand with both feet on edge of step, with the heels hanging off the edge (1). Keeping the body erect, rise onto the forefeet (2). Then slowly drop heels below level of the step and repeat (3). The modified calf raise (MCR); the participant will be asked to stand with both feet hip width apart on the edge of the step, with the heels hanging off the edge (1). Keeping the body in an erect position, rise up through the “big toe” (2). Then slowly drop heels below level of the step and repeat (3). Performing the straight leg raise (SLR); the participant will be positioned in a supine position, where they will be asked to bend knee of the non-affected side to flatten for back support (1). Lock knee of the affect leg out straight and lift leg to a height parallel to the bent knee (2). Then lower leg until it touches the bed, and then lift again, ensuring that the knee remains straight (3). The modified exercise “45deg straight leg raise; the participant will be asked to lay a supine position with a bent knee of the non-affected side to flatten and support lumbar spine (1). Lock the knee of the affected leg out straight, and externally rotate the thigh by turning the “toes outwards 45deg” (2). Lift the leg a height just below the opposite bent knee (3). Then lower leg until it touches the bed, and then lift again, ensuring that the knee remains straight (4). Performing the Wall squat (WS); the participant will be positioned with their back against the wall (1). Placing the heels about thigh width from the wall and hip width apart (2). Ensuring that knee do not extend over toes slowly lower the trunk until the knees are bent through a 60deg range, progressing further as tolerated (3). The modified wall squat (MWS) will include a ball squeeze with pressure cuff to maintain equal squeeze pressure. Participants will be asked positioned with their back against the wall (1), Place the heel about thigh width from the wall and hip width apart (2). Place a ball with sphygmomanometer between the knees and measure the level of squeeze (3). Ensuring that knee do not extend over toes, slowly lower the trunk until the knees are bent through a 60deg range, progressing further as tolerated (4). Performing the step up the participant will be asked to initially stand facing a step (step height=10-15cm)(1). Proceed to step up straight ahead with the affected leg, ensuring that the knee always remains on a line between the hip and foot until the unaffected foot is on the step (2). Emphasis should be placed on maintaining balance, correct upright posture, abdominal bracing, good knee alignment and pelvic/gluteal control (3). Slowly lower back down on the unaffected leg maintaining correct balance, knee alignment with abdominal and pelvic control and repeat (4). The modified variation step up will involve an altered foot position marked out a specific angle. The participant will be required to proceed to step up straight onto the taped angle with the affected leg, ensuring that the knee always remains on a line between the hip and foot until the unaffected foot is on the step (2). Emphasis should be placed on maintaining balance, correct upright posture, abdominal bracing, good knee alignment and pelvic/gluteal control (3). Slowly Lower back down on the unaffected leg while maintaining correct balance, knee alignment with abdominal and pelvic control and repeat (4).