Search

The combination of plyometric and resistance training (RT) is frequently used to increase power-related adaptations. Since plyometric training is most effective when athletes are in a well-rested state, the acute effect of RT on plyometric performance should be carefully considered. Thus, 15 highly trained males (23.1±3.5 yrs, 1.80±0.06 m, 79.1±7.9 kg) completed a load- and volume-matched velocity-based RT session with 10% velocity loss (VL10) and traditional 1-repetition maximum-based RT session to failure (TRF) in a randomized order. Repeated sprints (5 × 15 m), countermovement jumps (CMJs), and drop jumps (DJs) were measured before, immediately after, and 24 h after both sessions. Lactate, heart rate, and perceived effort (RPE) were measured. Sprint, CMJ, and DJ revealed significant interaction effects (rANOVA p <0.001, ηp2 ≥0.63). Immediately afterward, sprint, DJ, and CMJ were less negatively affected (p ≤0.03, SMD≥|0.40|) by VL10 vs. TRF. Sprint and CMJ were already recovered 24 h post-testing and showed no significant differences between TRF and VL10 (p ≥0.07, SMD≤|0.21|). Twenty-four hours post-testing, DJs were still reduced during TRF but already recovered during VL10 (p =0.01, SMD=|0.70|). TRF resulted in higher lactate, heart rate, and RPE compared to VL10 (p ≤0.019, η p 2 ≥0.27, SMD≥|0.68|). In conclusion, the non-failure-based VL10 impairs jump and sprint performance less than the failure-based TRF approach, despite matched volume and intensity. [ABSTRACT FROM AUTHOR]

We aimed at assessing the validity and test-retest reliability of the inertial measurement unit-based Vmaxpro sensor compared with a Vicon 3D motion capture system and the T-Force sensor during an incremental 1-repetition maximum (1RM) test and at submaximal loads. Nineteen subjects reported to the laboratory for the 1RM test sessions, whereas 15 subjects carried out another 3 sessions consisting of 3 repetitions with 4 different intensities (30, 50, 70, and 90% of 1RM) to determine the intra- and interday reliability. The Vmaxpro sensor showed high validity (Vicon: R² =0.935; T-Force: R² = 0.968) but an overestimation of the mean velocities (MVs) of 0.06 ± 0.08 m·s-1 and 0.06 ± 0.06 m·s-1 compared with Vicon and T-Force, respectively. Regression analysis indicated a systematic bias that is increasing with higher MVs. The intraclass correlation coefficients (ICCs) for Vmaxpro were moderate to high for intraday (ICC: 0.662-0.938; p &8804#; 0.05) and for interday (ICC: 0.568-0.837; p ≤ 0.05) reliability, respectively. The Vmaxpro is a valid and reliable measurement device that can be used to monitor movement velocities within a training session. However, practitioners should be cautious when assessing movement velocities on separate days because of the moderate interday reliability. [ABSTRACT FROM AUTHOR]

Accuracy and test–retest reliability were assessed for two devices, PUSH Band 2.0 (PUSH) and Speed4lifts. Two identical sessions were performed 6–8 days apart. Twenty rugby league players performed three repetitions with 20%, 40%, 60% and 80% of estimated one repetition maximum for back squat (BS), front squat (FS), and bench press (BP). Velocity was recorded using PUSH, Speed4lifts and 3D motion analysis system (gold standard). Passing-Bablok regression analysis assessed agreement of velocity measures with the gold standard. Intraclass correlation coefficients (ICC) and coefficients of variation (CV) assessed test–retest reliability. PUSH and Speed4lifts were accurate for BS velocities <1.00 m/s and FS velocities <0.65 m/s. PUSH was accurate for BP velocities <0.65 m/s. Speed4lifts was accurate for BP velocities between 0.65–1.00 m/s. PUSH was reliable at all loads (ICC = 0.79–0.92; CV = 2.63–6.89%) except for 20% FS and BP (ICC = 0.49–0.64; CV = 3.13–3.62%). Speed4lifts was reliable at all loads (ICC = 0.70–0.96; CV = 2.57–4.26%) except for 20% BP (ICC = 0.59; CV = 4.59%). These results suggest that both devices are unsuitable for measuring the velocity of BS, FS and BP at faster velocities and at lighter loads. [ABSTRACT FROM AUTHOR]

When monitoring the mean concentric velocity (MCV) for velocity-based resistance training, often a threshold in the decline in the MCV is used to regulate the number of repetitions performed. However, it is not clear if the decline in the MCV is affected by the type of exercise or the relative load used. Therefore, the purpose of this study was to compare the decline in the MCV between the overhead press (OHP) and deadlift (DL) during sets to fatigue at different loads. Thirty individuals (23 ± 3 years) with current training experience with both the OHP and DL completed a 1 repetition maximum (1RM) protocol for the OHP and DL. Subjects then returned to the laboratory on 2 separate occasions and completed 1 set of the OHP and DL to volitional fatigue at either 70 or 90% of their 1RM in a randomized order. The open barbell system measured the MCV of all repetitions. The absolute and relative (%) decline in the MCV was calculated for each condition and compared between loads (70 vs. 90% 1RM) and between lifts (OHP vs. DL). An alpha level of 0.05 was used at the criterion for statistical significance. The absolute decline in the MCV was greatest for the 70% OHP condition (0.36 ± 0.12 m⋅s-1) followed by 90% OHP (0.19 ± 0.10 m⋅s-1), 70% DL(0.16 ± 0.08 m⋅s-1), and 90% DL(0.09 ± 0.06 m⋅s-1); all were significantly different from one another (p < 0.05) except for 70% DL vs. 90% OHP (p 5 0.441). There was a greater relative decline in the MCV for the OHP compared with the DL (50.1 ± 11.8% vs. 28.5 ± 11.8%; p < 0.001) and for 70% 1RM compared with 90% 1RM(44.5 ± 12.0% vs. 34.1 ± 12.0%; p < 0.001). These data suggest the decline in the MCV is both exercise and load specific. Applying a uniform velocity decline threshold for velocity-based training may reduce training volume to different extents depending on the exercise and relative load used. [ABSTRACT FROM AUTHOR]

The aim of this study was to assess the criterion validity, interunit reliability (accounting for technological and biological variance), and between-day reliability of a novel optic laser device (FLEX) for quantifying mean concentric velocity. To assess the validity against a three-dimensional motion capture system and interunit reliability with both technological and biological variation, 18 men and women completed repetitions at 20, 40, 60, 80, 90, and 100% of one repetition maximum in the free-weight barbell back squat and bench press. To assess interunit (technological only) reliability, a purpose-built, calibrated rig completed a set protocol with 2 devices. To assess between-day reliability of the technology, the same protocol was repeated 21 days later. Standardized bias, typical error of the estimate (TEE; %), and Pearson's correlation coefficient (r) were used to assess validity, whereas typical error and coefficient of variation (CV%) were calculated for reliability. Overall, TEE (±90 CL) between the FLEX and criterion measure was 0.03 (±0.004) and 0.04 (±0.005) m·s−1 in the back squat and bench press, respectively. For measures of reliability, overall interunit technological variance (CV% [± 90% confidence interval]) was 3.96% (3.83–4.12) but increased to 9.82% (9.31–10.41) and 9.83% (9.17–10.61) in the back squat and bench press, respectively, when biological variance was introduced. Finally, the overall between-day reliability was 3.77% (3.63–3.91). These findings demonstrate that the FLEX provides valid and reliable mean concentric velocity outputs across a range of velocities. Thus, practitioners can confidently implement this device for the monitoring and prescription of resistance training loads. [ABSTRACT FROM AUTHOR]