Objectives: To investigate peripheral (RPEP) and central (RPEC) rating of perceived exertion during wheelchair propulsion in untrained able-bodied (AB) participants, and trained wheelchair rugby athletes with and without cervical spinal cord injury (CSCI).Design: Cross-sectional study.Methods: 38 participants (AB: n = 20; wheelchair rugby athletes with CSCI: n = 9; without CSCI: n = 9) completed an incremental wheelchair propulsion test to exhaustion on a motorised treadmill. Gas exchange measures and heart rate (HR) were collected throughout. RPEP and RPEC on the Category Ratio-10 were verbally recorded each minute. Blood lactate concentration ([BLa]) was determined posttest.Results: Between 50-100% peak oxygen uptake (V O2peak), RPEP was greater than RPEC in AB (p < 0.05), but not in athletes with (p = 0.07) or without (p = 0.16) CSCI. RPEP was greater in AB compared to players with CSCI (Effect sizes: 1.24-1.62), as were respiratory exchange ratio (1.02 ± 0.10 vs. 0.82 ± 0.11, p < 0.05) and [BLa]peak (7.98 ± 2.53 vs 4.66 ± 1.57 mmol•L -1 ). RPEC was greater in athletes without CSCI compared to those with CSCI (Effect sizes: 0.70-1.38), as were HR (166 ± 20 vs. 104 ± 15 beats•min -1 , p < 0.05) and ventilation (59.2 ± 28.8 vs. 35.1 ± 16.6 L•min -1 , p = 0.01). Conclusion:RPEP was dominant over RPEC during wheelchair propulsion for untrained AB participants.For athletes with CSCI, lower RPEP and RPEC were reported at the same %V O2peak compared to those without CSCI. The mechanism for this remains to be fully elucidated.

The purpose of this study was to examine the reliability of load-velocity profiles (LVPs) and validity of 1-repetition maximum (1-RM) prediction methods in the back-squat using the novel Vitruve linear position transducer (LPT). Twenty-five men completed a back-squat 1-RM assessment followed by 2 LVP trials using five incremental loads (20%–40%–60%–80%–90% 1-RM). Mean propulsive velocity (MPV), mean velocity (MV) and peak velocity (PV) were measured via a (LPT). Linear and polynomial regression models were applied to the data. The reliability and validity criteria were defined a priori as intraclass correlation coefficient (ICC) or Pearson correlation coefficient ( r) > 0.70, coefficient of variation (CV) ≤10%, and effect size ( ES) <0.60. Bland-Altman analysis and heteroscedasticity of errors ( r2) were also assessed. The main findings indicated MPV, MV and PV were reliable across 20%–90% 1-RM (CV < 8.8%). The secondary findings inferred all prediction models had acceptable reliability (CV < 8.0%). While the MPV linear and MV linear models demonstrated the best estimation of 1-RM (CV < 5.9%), all prediction models displayed unacceptable validity and a tendency to overestimate or underestimate 1-RM. Mean systematic bias (−7.29 to 2.83 kg) was detected for all prediction models, along with little to no heteroscedasticity of errors for linear ( r2 < 0.04) and polynomial models ( r2 < 0.08). Furthermore, all 1-RM estimations were significantly different from each other ( p < 0.03). Concludingly, MPV, MV and PV can provide reliable LVPs and repeatable 1-RM predictions. However, prediction methods may not be sensitive enough to replace direct assessment of 1-RM. Polynomial regression is not suitable for 1-RM prediction.

This study examined the test re-test, intrarater and interrater reliability of joint kinematics from the coach's Eye smartphone application. Twenty-two males completed a 1-repetition maximum (1-rM) assessment followed by 2 identical sessions using 5 incremental loads (20, 40, 60, 80, 90% 1-rM). Peak flexion angles at the hip, knee, and ankle joints were assessed using 1 experienced practitioner and 1 inexperienced practitioner. the acceptable reliability thresholds were defined as intraclass correlation coefficient (Icc) r > 0.70 and coefficient of variation cv ≤ 10%. the test re-test reliability of peak hip and knee flexion were reliable across 20-90% 1-rM (r > 0.64; cv < 4.2%), whereas peak ankle flexion was not reliable at any loaded condition (r > 0.70; cv < 20.4%). no significant differences were detected between trials (p > 0.11). the intrarater reliability was near perfect (r > 0.90) except for peak ankle flexion (r > 0.85). the interrater reliability was nearly perfect (r > 0.91) except for hip flexion at 80% 1-rM and ankle flexion at 20% (r > 0.77). concludingly, the coach's Eye application can produce repeatable assessments of joint kinematics using either a single examiner or 2 examiners, regardless of experience level. the coach's Eye can accurately monitor squat depth.