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Purpose: To investigate the indirect measurement of 1-repetition-maximum (1RM) free-weight half-squat in high-level sprinters using the load–velocity relationship. Methods: Half-squat load and velocity data from 11 elite sprinters were collected in 2 separate testing sessions. Approximately 24 hours prior to the first testing session, sprinters completed a fatiguing high-intensity training session consisting of running intervals, staircase exercises, and body-weight exercises. Prior to the second testing session, sprinters had rested at least 48 hours. Two different prediction models (multiple-point method, 2-point method) were used to estimate 1RM based on the load and either mean or peak concentric velocity data of submaximal lifts (40%–90% 1RM). The criterion validity of all methods was examined through intraclass correlation coefficients, coefficient of variation (CV%), Bland–Altman plots, and the SEM. Results: None of the estimations were significantly different from the actual 1RM. The multiple-point method showed higher intraclass correlation coefficients (.91 to.97), with CVs from 3.6% to 11.7% and SEMs from 5.4% to 10.6%. The 2-point method showed slightly lower intraclass correlation coefficients (.76 to.95), with CVs 1.4% to 17.5% and SEMs from 9.8% to 26.1%. Bland–Altman plots revealed a mean random bias in estimation of 1RM for both methods (mean and peak velocity) ranging from 1.06 to 13.79 kg. Conclusion: Velocity-based methods can be used to roughly estimate 1RM in elite sprinters in the rested and fatigued conditions. However, all methods showed variations that limit their applicability for accurate load prescription for individual athletes. [ABSTRACT FROM AUTHOR]

Purpose: To compare the accuracy of nine 1-repetition maximum (1RM) prediction methods during the paused and touch-and-go bench press exercises performed in a Smith machine. Method: A total of 86 men performed 2 identical sessions (incremental loading test until reaching the 1RM followed by a set to failure) in a randomized order during the paused and touch-and-go bench press exercises. Individualized load–velocity relationships were modeled by linear and polynomial regression models considering 4 loads (45%–60%–75%–90% of 1RM) (multiple-point methods) and considering only 2 loads (45%–90% of 1RM) by a linear regression (2-point method). Three minimal velocity thresholds were used: the general velocity of 0.17 m·s−1 (general velocity of the 1RM [V1RM]), the velocity obtained when lifting the 1RM load (individual V1RM), and the velocity obtained during the last repetition of a set to failure. Results: The 1RM prediction methods were generally valid (range: r =.96–.99, standard error of the estimate = 2.8–4.9 kg or 4.6%–8.0% of 1RM). The multiple-point linear method (2.79 [2.29] kg) was more precise than the multiple-point polynomial method (3.54 [3.31] kg; P =.013), but no significant differences were observed when compared with the 2-point method (3.09 [2.66] kg, P =.136). The velocity of the last repetition of a set to failure (3.47 [2.97] kg) was significantly less precise than the individual V1RM (2.91 [2.75] kg, P =.009) and general V1RM (3.00 [2.65] kg, P =.010). Conclusions: Linear regression models and a general minimal velocity threshold of 0.17 m·s−1 should be recommended to obtain a quick and precise estimation of the 1RM during the bench press exercise performed in a Smith machine. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to examine the reliability and validity of load−velocity (L–V) relationship variables obtained through the 2-point method using different load combinations and velocity variables. Methods: Twenty men performed 2 identical sessions consisting of 2 countermovement jumps against 4 external loads (20 kg, 40 kg, 60 kg, and 80 kg) and a heavy squat against a load linked to a mean velocity (MV) of 0.55 m/s (load0.55). The L–V relationship variables (load-axis intercept (L0), velocity-axis intercept (v0), and area under the L–V relationship line (Aline)) were obtained using 3 velocity variables (MV, mean propulsive velocity (MPV), and peak velocity) by the multiple-point method including (20–40–60–80–load0.55) and excluding (20–40–60–80) the heavy squat, as well as from their respective 2-point methods (20–load0.55 and 20–80). Results: The L–V relationship variables were obtained with an acceptable reliability (coefficient of variation (CV) ≤ 7.30%; intra-class correlation coefficient ≥ 0.63). The reliability of L0 and v0 was comparable for both methods (CVratio (calculated as higher value/lower value): 1.11–1.12), but the multiple-point method provided Aline with a greater reliability (CVratio = 1.26). The use of a heavy squat provided the L–V relationship variables with a comparable or higher reliability than the use of a heavy countermovement jump load (CVratio: 1.06–1.19). The peak velocity provided the load–velocity relationship variables with the greatest reliability (CVratio: 1.15–1.86) followed by the MV (CVratio: 1.07–1.18), and finally the MPV. The 2-point methods only revealed an acceptable validity for the MV and MPV (effect size ≤ 0.19; Pearson's product-moment correlation coefficient ≥ 0.96; Lin's concordance correlation coefficient ≥ 0.94). Conclusion: The 2-point method obtained from a heavy squat load and MV or MPV is a quick, safe, and reliable procedure to evaluate the lower-body maximal neuromuscular capacities through the L–V relationship.

• The load−velocity relationship variables (L 0 , v 0 , and A line) are obtained with an acceptable reliability during the countermovement jump exercise regardless of the method (multiple-point vs. 2-point), load combination (heavy-squat vs. heavy countermovement jump), and velocity variable (mean velocity vs. mean propulsive velocity vs. peak velocity). • The concurrent validity of the 2-point method with respect to the multiple-point method was only acceptable for mean velocities. • The 2-point method obtained from a heavy squat load and mean velocities is a quick, safe, and reliable procedure to evaluate the maximal neuromuscular capacities of lower-body muscles through the assessment of the load−velocity relationship variables. This study aimed to examine the reliability and validity of load−velocity (L–V) relationship variables obtained through the 2-point method using different load combinations and velocity variables. Twenty men performed 2 identical sessions consisting of 2 countermovement jumps against 4 external loads (20 kg, 40 kg, 60 kg, and 80 kg) and a heavy squat against a load linked to a mean velocity (MV) of 0.55 m/s (load 0.55). The L–V relationship variables (load-axis intercept (L 0), velocity-axis intercept (v 0), and area under the L–V relationship line (A line)) were obtained using 3 velocity variables (MV, mean propulsive velocity (MPV), and peak velocity) by the multiple-point method including (20–40–60–80–load 0.55) and excluding (20–40–60–80) the heavy squat, as well as from their respective 2-point methods (20–load 0.55 and 20–80). The L–V relationship variables were obtained with an acceptable reliability (coefficient of variation (CV) ≤ 7.30%; intra-class correlation coefficient ≥ 0.63). The reliability of L 0 and v 0 was comparable for both methods (CV ratio (calculated as higher value/lower value): 1.11–1.12), but the multiple-point method provided A line with a greater reliability (CV ratio = 1.26). The use of a heavy squat provided the L–V relationship variables with a comparable or higher reliability than the use of a heavy countermovement jump load (CV ratio : 1.06–1.19). The peak velocity provided the load–velocity relationship variables with the greatest reliability (CV ratio : 1.15–1.86) followed by the MV (CV ratio : 1.07–1.18), and finally the MPV. The 2-point methods only revealed an acceptable validity for the MV and MPV (effect size ≤ 0.19; Pearson's product-moment correlation coefficient ≥ 0.96; Lin's concordance correlation coefficient ≥ 0.94). The 2-point method obtained from a heavy squat load and MV or MPV is a quick, safe, and reliable procedure to evaluate the lower-body maximal neuromuscular capacities through the L–V relationship. [Display omitted] [ABSTRACT FROM AUTHOR]

Purpose: An a posteriori multicenter reliability study was conducted to compare the reliability of the outcomes derived from the linear force–velocity (F–V) relationship (F-intercept [F0], V-intercept [V0], F–V slope, and maximum power [Pmax]) using a 2-point method based on 2 distant loads with respect to a multiple-point method based on 4 proximal loads and a multiple-point method that considered all 6 tested loads. Method: Data from 63 healthy men derived from 3 studies were analyzed. The F–V relationship obtained from the bench-press-throw exercise was determined in 2 separate sessions using 3 different combinations of loads: 2-point method (20–70% of 1-repetition maximum [1RM]), 4-load multiple-point method (30–40–50–60% of 1RM), and 6-load multiple-point method (20–30–40–50–60–70% of 1RM). Reliability was assessed through the coefficient of variation (CV), whereas a CVratio of 1.15 was deemed as the smallest important ratio. Results: The 2-point method provided the outcomes of the F–V relationship with greater reliability than the 4-load multiple-point method (F0, 3.58% vs 4.53%, CVratio = 1.27; V0, 5.58% vs 7.85%, CVratio = 1.41; F–V slope, 8.57% vs 11.99%, CVratio = 1.40; Pmax, 4.33% vs 4.81%, CVratio = 1.11). The reliability of the 6-load multiple-point method was comparable to the 2-point method (F0, 3.53%, CVratio = 1.01; V0, 5.32%, CVratio = 1.05; F–V slope, 8.38%, CVratio = 1.02; P0, 3.74%, CVratio = 1.16). Conclusion:The distance between experimental points is more important for obtaining a reproducible F–V relationship than the number of experimental points; therefore, the 2-point method could be recommended for a quicker assessment of the F–V relationship. [ABSTRACT FROM AUTHOR]

This study aimed to compare and associate the magnitude of the load–velocity relationship variables between the multiple-point and two-point methods and between the concentric-only and eccentric–concentric prone bench pull (PBP) variants. Twenty-three resistance-trained males completed a preliminary session to determine the concentric-only PBP one-repetition maximum (1 RM) and two experimental sessions that only differed in the PBP variant evaluated. In each experimental session they performed three repetitions against the 14 kg load (L1), two repetitions against the 85% 1 RM load (L4), three repetitions against an equidistant intermediate light load (L2), two repetitions against an equidistant intermediate heavy load (L3), and 1–5 1 RM attempts. The load–velocity relationship variables (i.e., load–axis intercept, velocity–axis intercept, and area under the load–velocity relationship line) were obtained from the multiple-point (L1-L2-L3-L4) and two-point (L1-L4) methods. All load–velocity relationship variables presented greater magnitudes when obtained by the two-point method compared with the multiple-point method (p < 0.001, ESrange = 0.17–0.43), while the load–velocity relationship variables were comparable between both PBP variants (p ≥ 0.148). In addition, the load–velocity relationship variables were highly correlated between both methods (rrange = 0.972–0.995) and PBP variants (rrange = 0.798–0.909). When assessing the load–velocity relationship variables, practitioners should prescribe only two loads, as this maximises the magnitudes of the variables and decreases fatigue. [ABSTRACT FROM AUTHOR]

Purpose: To explore the feasibility of the linear force-velocity (F-V) modeling approach to detect selective changes of F-V parameters (ie, maximum force [F0], maximum velocity [V0], F-V slope [a], and maximum power [P0]) after a sprint-training program. Methods: Twenty-seven men were randomly assigned to a heavy-load group (HLG), light-load group (LLG), or control group (CG). The training sessions (6 wk x 2 sessions/wk) comprised performing 8 maximal-effort sprints against either heavy (HLG) or light (LLG) resistances in leg cycle-ergometer exercise. Pre- and posttest consisted of the same task performed against 4 different resistances that enabled the determination of the F-V parameters through the application of the multiple-point method (4 resistances used for the F-V modeling) and the recently proposed 2-point method (only the 2 most distinctive resistances used). Results: Both the multiple-point and the 2-point methods revealed high reliability (all coefficients of variation <5% and intraclass correlation coefficients >.80) while also being able to detect the group-specific training-related changes. Large increments of F0, a, and P0 were observed in HLG compared with LLG and CG (effect size [ES] = 1.29-2.02). Moderate increments of V0 were observed in LLG compared with HLG and CG (ES = 0.87-1.15). Conclusions: Short-term sprint training on a leg cycle ergometer induces specific changes in F-V parameters that can be accurately monitored by applying just 2 distinctive resistances during routine testing. [ABSTRACT FROM AUTHOR]

An a-posteriori multicentre reliability study was conducted to compare the between-session reliability of the force-velocity relationship parameters (force-intercept [F0 ], velocity-intercept [v0 ], and maximum power [Pmax]) between different regression models during the bench press (BP) and bench press throw (BPT) exercises. Data from four and three studies were considered for the BP (n = 102) and BPT (n = 81) exercises, respectively. The force-velocity relationships were determined using five regression models: linear multiple-point, linear two-point, quadratic polynomial, hyperbolic, and exponential. All regression models provided F0 and Pmax with acceptable reliability (cut-off CV ≤ 9.45%; cut-off ICC ≥ 0.79) with the exceptions of F0 for the quadratic polynomial and hyperbolic models (BPT) and Pmax for the exponential model (BP and BPT). Only the linear multiple- and linear two-point models provided v0 with acceptable absolute reliability (cut-off CV ≤ 7.72%). Regardless of the exercise, the reliability of the three parameters was generally higher for the linear multiple- and two-point models compared to the other models (CVratio ≥ 1.22), and no significant differences were observed between multiple- and linear two-point models (CVratio ≤ 1.11). Linear regression models are recommended to maximise the reliability of the force-velocity relationship parameters during the BP and BPT exercises. [ABSTRACT FROM AUTHOR]

This study aimed to compare and associate the magnitude of the load–velocity relationship variables between the multiple-point and two-point methods and between the concentric-only and eccentric–concentric prone bench pull (PBP) variants. Twenty-three resistance-trained males completed a preliminary session to determine the concentric-only PBP one-repetition maximum (1 RM) and two experimental sessions that only differed in the PBP variant evaluated. In each experimental session they performed three repetitions against the 14 kg load (L1), two repetitions against the 85% 1 RM load (L4), three repetitions against an equidistant intermediate light load (L2), two repetitions against an equidistant intermediate heavy load (L3), and 1–5 1 RM attempts. The load–velocity relationship variables (i.e., load–axis intercept, velocity–axis intercept, and area under the load–velocity relationship line) were obtained from the multiple-point (L1-L2-L3-L4) and two-point (L1-L4) methods. All load–velocity relationship variables presented greater magnitudes when obtained by the two-point method compared with the multiple-point method (p < 0.001, ESrange = 0.17–0.43), while the load–velocity relationship variables were comparable between both PBP variants (p ≥ 0.148). In addition, the load–velocity relationship variables were highly correlated between both methods (rrange = 0.972–0.995) and PBP variants (rrange = 0.798–0.909). When assessing the load–velocity relationship variables, practitioners should prescribe only two loads, as this maximises the magnitudes of the variables and decreases fatigue.

An a-posteriori multicentre reliability study was conducted to compare the reliability and magnitude of the maximum power (Pmax) and optimal velocity (Vopt) between the force-power-velocity relationships during the leg cycle-ergometer and bench press throw exercises. The force-power-velocity relationships were determined in two separate sessions considering the values of force, velocity, and power collected under multiple loads. The force–velocity relationship was also determined from the force and velocity values collected under only the two most distant loads. Reliability of all regression models was high for Pmax and Vopt during the leg cycle-ergometer (CVrange: 1.73–2.98%) and for Pmax during the bench press throw (CVrange: 4.47–4.73%), while the reliability was acceptable for Vopt during the bench press throw (CVrange: 6.52–7.34%). Significant differences between the force-power-velocity relationships were observed for both Pmax and Vopt (P <.001). All regression models can be confidently used to determine Pmax and Vopt, but these should not be used interchangeably. [ABSTRACT FROM AUTHOR]

This study aimed to compare the reliability and magnitude of the force-velocity (F-V) relationship parameters between the squat jumps performed from the 90° (SJ90) and self-preferred knee angle (SJpref). A secondary aim was to explore the effect of the analysis procedure (force platform [FP] and Samozino's [SAM] method) and the number of loads tested (three- and two-point methods) on the F-V relationships. Twelve men were tested in two sessions during the SJ90 and SJpref. Two identical blocks of jumps were performed in each session against three external loads. The F-V relationship parameters (maximum force, maximum velocity, F-V slope and maximum power) were determined at each block through the FP and SAM procedures using the data collected under three (three-point method) or only the two most distant loads (two-point method). The average coefficient of variation (CV) of the four F-V parameters revealed a higher reliability for the SJ90 compared to the SJpref (5.86% vs. 7.55%; CVratio = 1.29) with more pronounced differences using the FP (CVratio = 1.43) than the SAM procedure (CVratio = 1.14), and higher reliability for the SAM compared to the FP (6.14% vs. 7.27%; CVratio = 1.18). The SJpref and SAM procedures provided comparable or higher magnitude of the F-V relationship parameters than the SJ90 and FP, respectively. The three- and two-point methods revealed a comparable reliability and trivial differences in the magnitude of the F-V relationship parameters. The routine testing procedure of the F-V relationship could be simplified using the SJpref, the SAM procedure and the two-point method. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to examine the reliability and validity of load-velocity (L-V) relationship variables obtained through the 2-point method using different load combinations and velocity variables., Methods: Twenty men performed 2 identical sessions consisting of 2 countermovement jumps against 4 external loads (20 kg, 40 kg, 60 kg, and 80 kg) and a heavy squat against a load linked to a mean velocity (MV) of 0.55 m/s (load 0.55 ). The L-V relationship variables (load-axis intercept (L 0 ), velocity-axis intercept (v 0 ), and area under the L-V relationship line (A line )) were obtained using 3 velocity variables (MV, mean propulsive velocity (MPV), and peak velocity) by the multiple-point method including (20-40-60-80-load 0.55 ) and excluding (20-40-60-80) the heavy squat, as well as from their respective 2-point methods (20-load 0.55 and 20-80)., Results: The L-V relationship variables were obtained with an acceptable reliability (coefficient of variation (CV) ≤ 7.30%; intra-class correlation coefficient ≥ 0.63). The reliability of L 0 and v 0 was comparable for both methods (CV ratio (calculated as higher value/lower value): 1.11-1.12), but the multiple-point method provided A line with a greater reliability (CV ratio  = 1.26). The use of a heavy squat provided the L-V relationship variables with a comparable or higher reliability than the use of a heavy countermovement jump load (CV ratio : 1.06-1.19). The peak velocity provided the load-velocity relationship variables with the greatest reliability (CV ratio : 1.15-1.86) followed by the MV (CV ratio : 1.07-1.18), and finally the MPV. The 2-point methods only revealed an acceptable validity for the MV and MPV (effect size ≤ 0.19; Pearson's product-moment correlation coefficient ≥ 0.96; Lin's concordance correlation coefficient ≥ 0.94)., Conclusion: The 2-point method obtained from a heavy squat load and MV or MPV is a quick, safe, and reliable procedure to evaluate the lower-body maximal neuromuscular capacities through the L-V relationship., Competing Interests: Competing interests The authors declare that they have no competing interests., (Copyright © 2022. Production and hosting by Elsevier B.V.)

Our study was designed to check the reliability of force–velocity (F-v) relationship outcome measures using flywheel (FW) squats. The main objectives at the primary level were to test intra-session reliability of mechanical parameters for ten equidistant FW loads, and at the secondary level, to test reliability and validity of the F-v relationship outcome measures in case any possible reduction in used loads and number of loads – compared to the 10-load method as a reference – is administered. Twenty-six subjects performed two sets of five squats with FW loads in the range 0.025–0.25 kg∙m2. Averaging six consecutive repetitions obtained ICC 2.k > 0.9 for mean force and mean velocity results. Consecutively averaged parameters at the primary level showed excellent inter-set reliability (ICC 2.1 > 0.9). The inverse F- v relationship was strong (R2 = 0.96). At the secondary level, Bland-Altman statistics showed decreasing bias and limits of agreement in combination with more loads. Theoretical maximal force and power showed smaller bias as F-v slope and theoretical maximal velocity for three loads or more. Four loads (0.025, 0.075, 0.225 and 0.25 kg∙m2) lowered bias to a 5% in relation to the reference F-v slope. In conclusion, six repetitions are required to obtain trustworthy force and velocity results. The results will contribute to standardising the methodology for assessing the mechanical capacities of leg muscles using FW resistance. Moreover, assessing individual F-v profile with reduced protocol may be a less fatiguing tool for prescribing exercise intensity and for assessing training adaptations. [ABSTRACT FROM AUTHOR]