Form Matters—Technical Cues in the Single Leg Heel Raise to Failure Test Significantly Change the Outcome: A Study of Convergent Validity in Australian Football Players

Practitioners routinely use the single leg heel raise (SLHR) to quantify calf function in healthy and injured populations. Despite this, approaches vary and the impact of cueing on SLHR performance and results interpretation in athletesis unknown. The primary aim of this study was to quantify the level of agreement of the cued versus non-cued SLHR tests. The secondary aim was to explore test outcomes and the potential impact of intrinsic factors. Cued and non-cued SLHR tests were conducted in fifty-one Australian football players (23 women, 28 men). Metronome pacing (60 bpm) and five key cues were included in the cued condition. The level of agreement (Bland–Altman) between tests was measured for capacity (repetitions to failure) and asymmetry. Data from 100 legs were included. The non-cued and cued SLHR tests demonstrated poor agreement in both capacity and asymmetry. More repetitions to failure were performed in the non-cued SLHR [Mean (SD) = 33.9 (10.3) vs. 21.9 (5.3), p < 0.001)], and men had greater capacity (36.8 (10.4) vs. 30.3 (9.2), p < 0.001). During the cued SLHR, older players (age ≥ 30 years: −5.1 repetitions, p = 0.01) and Indigenous players (−3.4 repetitions, p = 0.002) and had reduced calf muscle function. Cueing the SLHR test significantly changes the result—outcomes are not comparable or interchangeable with the commonly used non-cued SLHR. These findings can guide practitioners quantifying calf capacity.