Evaluating the Level of Agreement Between Goniometer Measurements and Algorithm to Determine Wall Squat Position

The isometric wall squat exercise has been used as an intervention in several research studies However, how the protocol is delivered can vary between researchers; for example, participants can be instructed to adjust their foot position to keep lower leg vertical with the wall while lowering onto a squat position; while others use a standard goniometer in conjunction with a spirit level to establish knee joint angle and limb position. Therefore, to ensure study reliability and repeatability a standardised protocol to ensure consistent limb position needs to be established. Traditionally, measurement of joint angles and limb range of movement (ROM) using a standard universal goniometer is deemed gold standard in clinical settings. While the goniometer is portable and relatively inexpensive it has several limitations in terms of practical use. Firstly, both hands are required to align and stabilise the goniometer positioning, and maintaining the alignment during movement can be problematic. Also, the use of a standard universal goniometer requires alignment with specified bony landmarks, some of which are not visually located or palpated with ease and require a good level of underpinning anatomical knowledge. Moreover, the level of accuracy in goniometer alignment can be further reduced when observing intertester measurements. Consequently, challenges with goniometer alignment and stabilisation, alongside intertester variability, may lead to errors in measurement.

Using a standard universal goniometer in combination with a spirit level to establish the isometric wall squat position requires a baseline weight bearing position to be maintained while correct limb positions and knee joint angle are established, and squat height measurements recorded. This may be time consuming, uncomfortable, and difficult to maintain for untrained populations, particularly within the more acute degree angles, leading to difficulties in determining accurate baseline measurements. Therefore, an alternative method to determine squat position would be beneficial for the development and standardisation of the protocol. As linear bone growth typically ceases at ~18 yrs for females, and ~21yrs for males, limb length in the healthy adult population remains relatively consistent. Recent research has explored the use of artificial intelligence algorithms to predict overall height from femoral and tibial bone lengths. Therefore, based on this principle, this study aims to explore if using a squat height calculator algorithm, utilising lower limb bone lengths, agrees with gold standard universal goniometer measurements to ascertain positioning for an isometric wall squat at specific knee joint angles

Inclusion criteria

• >21 years
• Written informed consent provided

Exclusion criteria

• Orthopaedic problems or injury affecting the hip, knee, or ankle joints
• Inability to stand unaided and hold a static position for >5 minutes