Objective: To explore (1) the goodness of fit of generalized and individualized relationships between the maximum number of repetitions performed to failure (RTF) and the fastest mean velocity and peak velocity of the sets (RTF–velocity relationships), (2) the between-sessions reliability of mean velocity and peak velocity values associated with different RTFs, and (3) whether the errors in the prediction of the RTF under fatigued and nonfatigued conditions differ between generalized and individualized RTF–velocity relationships. Methods: Twenty-three sport-science students performed 4 testing sessions with the prone bench pull exercise in a Smith machine: a 1-repetition-maximum [1RM] session, 2 identical sessions consisting of singles sets of RTF against 4 randomized loads (60%–70%–80%–90%1RM), and 1 session consisting of 4 sets of RTF against the 75%1RM. Results: Individualized RTF–velocity relationships presented a higher goodness of fit (r2 = .96–.97 vs .67–.70) and accuracy (absolute errors = 2.1–2.9 repetitions vs 2.8–4.3 repetitions) in the prediction of the RTF than generalized RTF–velocity relationships. The reliability of the velocity values associated with different RTFs was generally high (average within-subject coefficient of variation = 4.01% for mean velocity and 3.98% for peak velocity). The error in the prediction of the RTF increased by ~1 repetition under fatigue (ie, set 1 vs sets 2–4). Conclusions: Individualized RTF–velocity relationships can be used with acceptable precision and reliability to prescribe the loads associated with a given RTF during the match a specific XRM during the prone bench pull exercise, but a lower accuracy is expected in a fatigued state.

Jiménez-Alonso, A, García-Ramos, A, Cepero, M, Miras-Moreno, S, Rojas, FJ, and Pérez-Castilla, A. Velocity performance feedback during the free-weight bench press testing procedure: An effective strategy to increase the reliability and one repetition maximum accuracy prediction. J Strength Cond Res 36(4): 1077–1083, 2022—This study aimed to determine whether the verbal provision of velocity performance feedback during the free-weight bench press (BP) exercise influences (a) the within-session reliability and magnitude of mean concentric velocity (MCV) values recorded against a range of submaximal loads and (b) the accuracy of the individualized load-velocity profile to estimate the BP 1 repetition maximum (1RM). Fifteen men (BP 1RM relative to body mass = 1.08 ± 0.22) performed an incremental loading test until reaching the 1RM on 2 separate sessions. Subjects received verbal velocity performance feedback in 1 session (knowledge of results [KR]), and no KR was provided in another session (Control). A linear velocity transducer was used to collect the MCV against 4 loads (40-55-70-85% 1RM), and the BP 1RM was estimated from the individualized load-velocity relationship modeled through the multiple-point (40-55-70-85% 1RM) and 2-point methods (40-85% 1RM). The KR condition provided a higher reliability (coefficient of variation [CV]: KR = 2.41%, Control = 3.54%; CV ratio = 1.47) and magnitude (p = 0.001; effect size [ES] = 0.78) of MCV for the 40% 1RM, but no significant differences in reliability (CV ratio ≤1.15) nor in the magnitude (p ≥ 0.058; ES range = 0.00–0.32) were observed for higher loads. The accuracy in the estimation of the 1RM was higher for the KR (absolute errors: multiple-point = 3.1 ± 2.3 kg; 2-point = 3.5 ± 2.1 kg) compared with the Control condition (absolute errors: 4.1 ± 1.9 kg for both multiple-point and 2-point methods). These results encourage the provision of verbal velocity performance feedback during BP testing procedures.

Effect of augmented feedback on velocity performance during strength-oriented and power-oriented resistance training sessions. J Strength Cond Res 36(6): 1511-1517, 2022-This study examined the effects of providing instantaneous velocity feedback (knowledge of results [KR]) on velocity maintenance across multiple sets during strength-oriented and power-oriented resistance training (RT) sessions. Seventeen men completed 2 strength-oriented RT sessions (4 sets of 5 repetitions at 75% of 1 repetition maximum [1RM] during the back squat [SQ] and bench press [BP] exercises) in 1 week and 2 power-oriented RT sessions (4 sets of 5 repetitions at 30% of 1RM during the countermovement jump [CMJ] and BP throw [BPT] exercises) in another week. Subjects received verbal velocity performance feedback in 1 session (KR) and no KR was provided in another session. Greater velocities during the 4 sets of both strength-oriented (from 4.6 to 11.6%) and power-oriented (from 1.4 to 3.5%) RT sessions were observed. The increments in velocity performance during the KR condition were greater for the CMJ (2.25 6 0.14 vs. 2.18 6 0.17 m•s 21 ; 3.0%) than the BPT (2.33 6 0.13 vs. 2.29 6 0.16 m•s 21 ; 1.7%) and similarly for the SQ (0.59 6 0.07 vs. 0.55 6 0.06 m•s 21 ; 7.5%) and BP (0.47 6 0.09 vs. 0.44 6 0.07 m•s 21 ; 7.8%). The raw differences in the RT velocity for BPT were positively correlated with the raw differences in the RT velocity for SQ (r 5 0.524; p 5 0.031) and CMJ (r 5 0.662; p 5 0.004), but the remaining correlations did not reach a statistical significance (r # 0.370; p $ 0.123). Although these results support the provision of velocity performance feedback to increase training quality regardless of the type of RT session, the positive effect of KR seems to be more accentuated during strengthoriented compared with power-oriented RT sessions.

Pérez-Castilla, A, Miras-Moreno, S, Janicijevic, D, and García-Ramos, A. Velocity loss is not an accurate predictor of the percentage of completed repetitions during the prone bench pull exercise. J Strength Cond Res 37(5): 1001–1008, 2023—The primary aim of this study was to explore the goodness of fit and accuracy of both general and individual relationships between the magnitude of velocity loss (%VL) and the percentage of performed repetitions with respect to the maximal number of repetitions that can be completed to failure (%Rep) during the Smith machine prone bench pull exercise. Fifteen male sports science students completed a preliminary session to determine the bench pull one-repetition maximum (1RM) and 2 identical experimental sessions separated by 48–72 hours. In each experimental session, subjects randomly performed single sets of repetitions to failure separated by 10 minutes against the 60% 1RM, 70% 1RM, and 80% 1RM during the Smith machine bench pull exercise. Individual %Rep-%VL relationships presented a greater goodness of fit than general %Rep-%VL relationships at the 60% 1RM (R2 = 0.85–0.97 vs. 0.79–0.85), 70% 1RM (R2 = 0.84–0.99 vs. 0.77–0.84), and 80% 1RM (R2 = 0.84–1.00 vs. 0.74–0.80). However, the accuracy (absolute errors) in estimating the %Rep during the second testing session based on the %Rep-%VL equations obtained in the first testing session did not differ between the individual and general %Rep-%VL equations in 8 of 9 comparisons (p ≥ 0.102). The absolute errors between the actual and predicted %REP were unacceptable (>10%) in 11 of 18 comparisons, and acceptable (5–10%) in 7 of 18 comparisons. These results highlight that the %Rep cannot be estimated with high degree of accuracy from VL recordings during the Smith machine bench pull exercise, regardless of whether individual or general Rep-%VL relationships are considered.

This study explored the impact of different frequencies of knowledge of results (KR) on velocity performance during ballistic training. Fifteen males completed four identical sessions (three sets of six repetitions at 30% one-repetition maximum during the countermovement jump and bench press throw) with the only difference of the KR condition provided: no feedback, velocity feedback after the first half of repetitions of each set (HalfKR), velocity feedback immediately after each repetition (ImKR), and feedback of the average velocity of each set (AvgKR). When compared with the control condition, the ImKR reported the highest velocity performance (1.9–5.3%), followed by the HalfKR (1.3–3.6%) and AvgKR (0.7–4.3%). These results support the verbal provision of velocity performance feedback after every repetition to induce acute improvements in velocity performance.

SA. Selective effect of different high-intensity running protocols on resistance training performance. J Strength Cond Res 37(6): e369-e375, 2023-This study aimed to explore the acute effect of 2 high-intensity running protocols (high-intensity interval training [HIIT] and sprint interval training [SIT]) on resistance training (RT) performance and their combined effect on the lower-body maximal neuromuscular capacities. Eighteen healthy subjects randomly completed 3 experimental protocols: only RT, HIIT + RT, and SIT + RT. Characteristics of the RT protocol include 3 back-squat sets of 10 repetitions or 20% velocity loss against 60% of 1 repetition maximum with 3 minutes of interset rest. Characteristics of the high-intensity running protocols include HIIT (4 intervals of 4 minutes at ;110% of functional threshold power with 3 minutes of interinterval rest) and SIT (6 all-out sprints of 30 seconds with 4 minutes and 24 seconds of interinterval rest). The force-velocity relationship (maximal values of force [F 0 ], velocity [v 0 ], and power [P max ]) was evaluated at the beginning and at the end of each experimental protocol. The number of back-squat repetitions (p 5 0.006; effect size [ES] 5 20.96), fastest velocity (p 5 0.003; ES 5 20.63), and average velocity (p 5 0.001; ES 5 20.73) were lower for the SIT + RT protocol compared with the RT protocol, but no significant differences were observed between the RT and HIIT + RT (p $T0.057; ES #.20.46, except 20.82 for the number of back-squat repetitions) and HIIT + RT and SIT + RT (p $T0.091; ES .02 0.35) protocols. The 3 protocols induced comparable decreases in v 0 and P max (F (2,34) 2,0.96; p $ 0.393), but F 0 tended to decrease after the SIT + RT protocol and to increase after the RT and HIIT + RT protocols (F (2,34) 5 4.37; p 5 0.035). Compared with RT alone, the data suggest that SIT deteriorates RT quality and F 0 capacity more than long-interval HIIT.

The present study investigates the effect of an acute intake of caffeine on the diurnal variation of neuromuscular performance in resistance-trained women. A total of 15 resistance-trained women participated in the current triple-blind, placebo-controlled, crossover experimental study. We assessed neuromuscular performance (i.e. ballistic (countermovement jump [CMJ] height and bench press throw [BPT] peak velocity), maximal strength (squat and bench press [BP] onerepetition maximum [1RM]), and strength-endurance [average velocity of the set during squat and number of repetitions-to-failure in BP]) four times at within 7 days. The participants ingested an acute dose of caffeine (3 mg/kg) or a placebo at 9-11 am and/or 17-19 pm. CMJ height (P = .016) and BP peak velocity (P = .012) were higher in the afternoon than in the morning. Compared to placebo, caffeine intake increased CMJ height by 3.1% in the morning and 1.6% in the afternoon (P = .035), but it had no effect on BPT peak velocity (P = .381). Maximal strength and strength-endurance performances were not affected by the time-of-day or caffeine intake (all P > .3). No significant interaction (time-of-day x substance) was observed in any of the above-mentioned outcomes (all P > .1). In conclusion, an acute dose of caffeine in the morning was effective to restore CMJ performance to levels found in the afternoon, while this effect was not observed neither in BPTpeak velocity nor in lower-and upper-body maximal strength and strength-endurance performance. Moreover, lower-and upper-body ballistic performance were greater in the afternoon than in the morning in resistance-trained women, while the acute intake of caffeine was only effective to increase CMJ height. Highlights. Ballistic performance is probably higher in the afternoon than in the morning in resistancetrained women. . An acute intake of caffeine is effective to increase countermovement jump performance.. The ingestion of an acute dose of caffeine in the morning restored countermovement jump performance to levels found in the afternoon.

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