# Reliability of a Portable Fixed Dynamometer During Different Isometric Hamstring Assessments
## 2 Methodology
### Procedures
#### 2.3.2. Supine 90:90 Hamstring Assessment Procedures  
The Hawkin TruStrength (HTS) was attached to a base plate with a compression pad attached to the opposite side, as shown in Figure 2A. The participant was asked to lie in a supine position with the base plate at a height relative to the participant's ankle height, while the knee and hip joint were at 90 degrees. Joint angles were measured using a goniometer to ensure accuracy and repeatability for each participant. The participant was instructed to place their arms over their chest to eliminate their usage during the test, as shown in Figure 2B. The non-working leg was placed in a straight position with the hip and knee at 180 degrees, allowing the leg to rest on the floor. The second tester would apply pressure downwards (see Figure 2C) to ensure there were no compensatory movements during the trial. Once the participant was in this position, the first tester instructed the participant to apply force as 'hard and as fast as possible' to ensure maximal force was reached immediately. The participant held the isometric contraction for 3 s and was instructed when to stop by the tester. The participant then rested for 40 s before completing the next trial on the same leg. The participant completed 5 trials per leg.  
Figure 1: (**A**) Hawkin TruStrength attached to rack and participant’s ankle. (**B**) Participant set up for standing hamstring assessment.  
Figure 2: (**A**) Hawkin TruStrength attached to base plate, (**B**) participant set up for the 90:90 assessment, (**C**) tester 2 applying pressure to the non-working leg.  
2.3.3. Standing 90:20 Hamstring Assessment Procedures  
The HTS was attached to a base plate with a compression pad attached to the opposite side, as shown in Figure 1A. The participant was instructed to be in a standing position with their back, head and buttocks against the wall, arms placed across their chest, and the non-testing leg placed against the wall (see Figure 3). The participant was instructed to bring the hip of the leg being tested to 90 degrees. The base plate with the HTS attached was placed relative to the participant's hip and knee angle to ensure the hip was at 90 degrees and the knee was at 20 degrees. This was measured by the first tester using a goniometer to ensure standardization and accuracy. The second tester used both hands and applied pressure to the leg against the wall to ensure the non-testing leg was against the wall, as shown in Figure 3. Once the participant was in this position, the first tester would instruct the participant to apply force 'as hard and as fast as possible' to ensure maximal force was reached immediately. Once 3 s had elapsed, the first tester instructed the participant to stop. If any compensatory movement was detected by tester 1 or 2, for example, rotation of the lumbo-pelvic region or loss of contact with the wall, the trial was considered invalid and was then repeated. The participant would then rest for 40 s before completing the next trial on the same leg. Each participant completed 5 trials per leg.