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This aims of this study were (I) to determine the velocity variable and regression model which best fit the load-velocity relationship during the free-weight prone bench pull exercise, (II) to compare the reliability of the velocity attained at each percentage of the one-repetition maximum (1RM) between different velocity variables and regression models, and (III) to compare the within- and between-subject variability of the velocity attained at each %1RM. Eighteen men (14 rowers and four weightlifters) performed an incremental test during the free-weight prone bench pull exercise in two different sessions. General and individual load-velocity relationships were modelled through three velocity variables (mean velocity [MV], mean propulsive velocity [MPV] and peak velocity [PV]) and two regression models (linear and second-order polynomial). The main findings revealed that (I) the general (Pearson's correlation coefficient [ r ] range = 0.964–0.973) and individual (median r = 0.986 for MV, 0.989 for MPV, and 0.984 for PV) load-velocity relationships were highly linear, (II) the reliability of the velocity attained at each %1RM did not meaningfully differ between the velocity variables (coefficient of variation [CV] range = 2.55–7.61% for MV, 2.84–7.72% for MPV and 3.50–6.03% for PV) neither between the regression models (CV range = 2.55–7.72% and 2.73–5.25% for the linear and polynomial regressions, respectively), and (III) the within-subject variability of the velocity attained at each %1RM was lower than the between-subject variability for the light-moderate loads. No meaningful differences between the within- and between-subject CVs were observed for the MV of the 1RM trial (6.02% vs . 6.60%; CV ratio = 1.10), while the within-subject CV was lower for PV (6.36% vs . 7.56%; CV ratio = 1.19). These results suggest that the individual load-MV relationship should be determined with a linear regression model to obtain the most accurate prescription of the relative load during the free-weight prone bench pull exercise.

The aims of the study were (i) to determine the reliability and concurrent validity of a functional electromechanical dynamometer (FEMD) to measure different isokinetic velocities, and (ii) to identify the real range of isokinetic velocity reached by FEMD for different prescribed velocities. Mean velocities were collected simultaneously with FEMD and a linear velocity transducer (LVT) in two sessions that were identical, consisting of 15 trials at five isokinetic velocities (0.40, 0.60, 0.80, 1.00, and 1.20 m·s−1) over a range of movement of 40 cm. The results obtained using each method were compared using Paired samples t-tests, Bland-Altman plots and the Pearson’s product–moment correlation coefficient, while the reliability was determined using the standard error of measurement and coefficient of variation (CV). The results indicate that the mean velocity values collected with FEMD and LVT were practically perfect correlations ( r > 0.99) with low random errors (<0.06 m·s−1), while mean velocity values were systematically higher for FEMD ( p < 0.05). FEMD provided a high or acceptable reliability for mean velocity (CV ≤ 0.24%), time to reach the isokinetic velocity (CV range = 1.68%–9.70%) and time spent at the isokinetic velocity (CV range = 0.53%–8.94%). These results suggest that FEMD offers valid and reliable measurements of mean velocity during a fixed linear movement, as well as a consistent duration of the isokinetic phase. FEMD could be an appropriate device to evaluate movement velocity during linear movements. More studies are needed to confirm the reliability and validity of FEMD to measure different velocity metrics during more complex functional exercises.

AimTo determine the absolute and relative reliability of functional trunk tests, using a functional electromechanical dynamometer to evaluate the isokinetic strength of trunk flexors and to determine the most reliable assessment condition, in order to compare the absolute and relative reliability of mean force and peak force of trunk flexors and to determine which isokinetic condition of evaluation is best related to the maximum isometric.MethodsTest-retest of thirty-seven physically active male student volunteers who performed the different protocols, isometric contraction and the combination of three velocities (V1 = 015 m s−1 , V2 = 0.30 m  s−1, V3 = 0.45 m s−1) and two range of movement (R1 = 25% cm ; R2 = 50% cm) protocols.ResultsAll protocols to evaluate trunk flexors showed an absolute reliability provided a stable repeatability for isometric and dynamic protocols with a coefficient of variation (CV) being below 10% and a high or very high relative reliability (0.69 < intraclass correlation coefficient [ICC] > 0.86). The more reliable strength manifestation (CV = 6.82%) to evaluate the concentric contraction of trunk flexors was mean force, with 0.15 m  s−1 and short range of movement (V1R1) condition. The most reliable strength manifestation to evaluate the eccentric contraction of trunk flexors was peak force, with 0.15 m  s−1 and a large range of movement (V1R2; CV = 5.07%), and the most reliable way to evaluate isometric trunk flexors was by peak force (CV = 7.72%). The mean force of eccentric trunk flexor strength with 0.45 m  s−1 and short range of movement (V3R1) condition (r = 0.73) was best related to the maximum isometric contraction.ConclusionFunctional electromechanical dynamometry is a reliable evaluation system for assessment of trunk flexor strength.

This study examined the differences in the bench press one-repetition maximum obtained by three different methods (direct method, lifts-to-failure method, and two-point method). Twenty young men were tested in four different sessions. A single grip width (close, medium, wide, or self-selected) was randomly used on each session. Each session consisted of an incremental loading test until reaching the one-repetition maximum, followed by a single set of lifts-to-failure against the 75% one-repetition maximum load. The last load lifted during the incremental loading test was considered the actual one-repetition maximum (direct method). The one-repetition maximum was also predicted using the Mayhew’s equation (lifts-to-failure method) and the individual load–velocity relationship modeled from two data points (two-point method). The actual one-repetition maximum was underestimated by the lifts-to-failure method (range: 1–2 kg) and overestimated by the two-point method (range: –3 to –1 kg), being these differences accentuated using closer grip widths. All predicted one-repetition maximums were practically perfectly correlated with the actual one-repetition maximum ( r ≥  0.95; standard error of the estimate ≤ 4 kg). The one-repetition maximum was higher using the medium grip width (83 ± 3 kg) compared to the close (80 ± 3 kg) and wide (79 ± 3 kg) grip widths ( P ≤  0.025), while no significant differences were observed between the medium and self-selected (81 ± 3 kg) grip widths ( P =  1.000). In conclusion, although both the Mayhew’s equation and the two-point method are able to predict the actual one-repetition maximum with an acceptable precision, the differences between the actual and predicted one-repetition maximums seem to increase when using close grip widths.