Velocity Performance Feedback During Ballistic Training: Which Is the Optimal Frequency of Feedback Administration?

Motor Control ◽  
2021 ◽  
Vol 25 (1) ◽  
pp. 19-32
Author(s):  
Alejandro Pérez-Castilla ◽  
Ainara Jiménez-Alonso ◽  
Mar Cepero ◽  
Sergio Miras-Moreno ◽  
F. Javier Rojas ◽  
...  

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.

2020 ◽  
Vol 41 (13) ◽  
pp. 921-928 ◽  
Author(s):  
Luis Rodiles-Guerrero ◽  
Fernando Pareja-Blanco ◽  
Juan Antonio León-Prados

AbstractThis study aimed to analyze the effects of three different velocity loss thresholds (10%: VL10, 30%: VL30 and 50%: VL50) on maximal strength and velocity at different intensities during bench press using a weight stack machine (WSM-BP). Forty-five men were randomly assigned to three groups: VL10 (n=15), VL30 (n=15) and VL50 (n=15), which followed a 5-week (15 sessions) velocity-based WSM-BP program. Assessments performed Pre- and Post-training included: a) estimated one-repetition maximum (1RM) in WSM-BP; b) average velocity attained against all absolute loads common to Pre- and Post-training tests in WSM-BP; c) average velocity attained against all absolute loads that were lifted equal to or faster than 0.8 m·s−1 at Pre-training (light loads); and d) average velocity attained against all absolute loads that were lifted slower than 0.8 m·s−1 at Pre-training (heavy loads). All groups showed significant improvements in 1RM, velocity against all loads, and velocity against heavy loads (P<0.001–0.01). However, only the VL10 group showed significant enhancements in velocity against light loads (P=0.05). Therefore, the VL10 group showed a higher training efficiency compared to VL30 and VL50 interventions, since it obtained similar benefits by performing fewer repetitions.


Author(s):  
Thomas Haugen ◽  
Will Hopkins ◽  
Felix Breitschädel ◽  
Gøran Paulsen ◽  
Paul Solberg

Purpose: To determine if generic off-ice physical fitness tests can provide useful predictions of ice hockey players’ match performance. Methods: Approximately 40 to 60 defenders and 70 to 100 forwards from the Norwegian male upper ice hockey league were tested for strength (1-repetition maximum in squat and bench press), power (40-m sprint and countermovement jump), and endurance (hanging sit-ups, chins, and 3000-m run) annually at the end of every preseason period between 2008 and 2017. Measures of match performance were each player’s season mean counts per match of assists, points, goals, penalty minutes, and plus-minus score. Results: Overall, match performance measures displayed trivial to small correlations with the fitness tests. More specifically, points per game had at most small correlations with measures of strength (range, approximately −0.2 to 0.3), speed (approximately −0.2 to 0.3), and endurance (approximately −0.1 to 0.3). After adjustments for age that showed moderate to large correlations with player match performance, multiple-regression analyses of each test measure still provided some predictability among players of the same age. However, players selected for the national team had substantially better mean scores for most tests and match performance measures than those not selected, with a moderate to large difference for age, 1-repetition maximum squat, and 1-repetition maximum bench press. Conclusions: Fitness tests had only marginal utility for predicting match performance in Norwegian hockey players, but those selected into the national team had better general fitness.


Author(s):  
Harry G. Banyard ◽  
James J. Tufano ◽  
Jonathon J.S. Weakley ◽  
Sam Wu ◽  
Ivan Jukic ◽  
...  

Purpose: To compare the effects of velocity-based training (VBT) and 1-repetition-maximum (1RM) percentage-based training (PBT) on changes in strength, loaded countermovement jump (CMJ), and sprint performance. Methods: A total of 24 resistance-trained males performed 6 weeks of full-depth free-weight back squats 3 times per week in a daily undulating format, with groups matched for sets and repetitions. The PBT group lifted with fixed relative loads varying from 59% to 85% of preintervention 1RM. The VBT group aimed for a sessional target velocity that was prescribed from pretraining individualized load–velocity profiles. Thus, real-time velocity feedback dictated the VBT set-by-set training load adjustments. Pretraining and posttraining assessments included the 1RM, peak velocity for CMJ at 30%1RM (PV-CMJ), 20-m sprint (including 5 and 10 m), and 505 change-of-direction test (COD). Results: The VBT group maintained faster (effect size [ES] = 1.25) training repetitions with less perceived difficulty (ES = 0.72) compared with the PBT group. The VBT group had likely to very likely improvements in the COD (ES = −1.20 to −1.27), 5-m sprint (ES = −1.17), 10-m sprint (ES = −0.93), 1RM (ES = 0.89), and PV-CMJ (ES = 0.79). The PBT group had almost certain improvements in the 1RM (ES = 1.41) and possibly beneficial improvements in the COD (ES = −0.86). Very likely favorable between-groups effects were observed for VBT compared to PBT in the PV-CMJ (ES = 1.81), 5-m sprint (ES = 1.35), and 20-m sprint (ES = 1.27); likely favorable between-groups effects were observed in the 10-m sprint (ES = 1.24) and nondominant-leg COD (ES = 0.96), whereas the dominant-leg COD (ES = 0.67) was possibly favorable. PBT had small (ES = 0.57), but unclear differences for 1RM improvement compared to VBT. Conclusions: Both training methods improved 1RM and COD times, but PBT may be slightly favorable for stronger individuals focusing on maximal strength, whereas VBT was more beneficial for PV-CMJ, sprint, and COD improvements.


2021 ◽  
Vol 11 (5) ◽  
pp. 71
Author(s):  
John F. T. Fernandes ◽  
Amelia F. Dingley ◽  
Amador Garcia-Ramos ◽  
Alejandro Perez-Castilla ◽  
James J. Tufano ◽  
...  

Background: This study determined the accuracy of different velocity-based methods when predicting one-repetition maximum (1RM) in young and middle-aged resistance-trained males. Methods: Two days after maximal strength testing, 20 young (age 21.0 ± 1.6 years) and 20 middle-aged (age 42.6 ± 6.7 years) resistance-trained males completed three repetitions of bench press, back squat, and bent-over-row at loads corresponding to 20–80% 1RM. Using reference minimum velocity threshold (MVT) values, the 1RM was estimated from the load-velocity relationships through multiple (20, 30, 40, 50, 60, 70, and 80% 1RM), two-point (20 and 80% 1RM), high-load (60 and 80% 1RM) and low-load (20 and 40% 1RM) methods for each group. Results: Despite most prediction methods demonstrating acceptable correlations (r = 0.55 to 0.96), the absolute errors for young and middle-aged groups were generally moderate to high for bench press (absolute errors = 8.2 to 14.2% and 8.6 to 20.4%, respectively) and bent-over-row (absolute error = 14.9 to 19.9% and 8.6 to 18.2%, respectively). For squats, the absolute errors were lower in the young group (5.7 to 13.4%) than the middle-aged group (13.2 to 17.0%) but still unacceptable. Conclusion: These findings suggest that reference MVTs cannot accurately predict the 1RM in these populations. Therefore, practitioners need to directly assess 1RM.


2013 ◽  
Vol 8 (4) ◽  
pp. 373-378 ◽  
Author(s):  
Stuart J. Cormack ◽  
Mitchell G. Mooney ◽  
Will Morgan ◽  
Michael R. McGuigan

Purpose:To determine the impact of neuromuscular fatigue (NMF) assessed from variables obtained during a countermovement jump on exercise intensity measured with triaxial accelerometers (load per minute [LPM]) and the association between LPM and measures of running activity in elite Australian Football.Methods:Seventeen elite Australian Football players performed the Yo-Yo Intermittent Recovery Test level 2 (Yo-Yo IR2) and provided a baseline measure of NMF (flight time:contraction time [FT:CT]) from a countermovement jump before the season. Weekly samples of FT:CT, coaches’ rating of performance (votes), LPM, and percent contribution of the 3 vectors from the accelerometers in addition to high-speed-running meters per minute at >15 km/h and total distance relative to playing time (m/min) from matches were collected. Samples were divided into fatigued and nonfatigued groups based on reductions in FT:CT. Percent contributions of vectors to LPM were assessed to determine the likelihood of a meaningful difference between fatigued and nonfatigued groups. Pearson correlations were calculated to determine relationships between accelerometer vectors and running variables, votes, and Yo-Yo IR2 score.Results:Fatigue reduced the contribution of the vertical vector by (mean ± 90% CI) –5.8% ± 6.1% (86% likely) and the number of practically important correlations.Conclusions:NMF affects the contribution of individual vectors to total LPM, with a likely tendency toward more running at low speed and less acceleration. Fatigue appears to limit the influence of the aerobic and anaerobic qualities assessed via the Yo-Yo IR2 test on LPM and seems implicated in pacing.


2021 ◽  
pp. 1-17
Author(s):  
Quan Cao ◽  
Huaizhong Shi ◽  
Weiqiang Xu ◽  
Chao Xiong ◽  
Zhaoliang Yang ◽  
...  

Abstract Vibro-impact drilling has been proven to be a viable technique for enhancing the Rate of Penetration (ROP) in deep and ultra-deep well drilling. It is essential to study the effects of impact parameters on impact energy and rock-drilling efficiency for impact tool design and operating parameter optimization. In this paper, the influences of impact parameters including impact frequency, dynamic loading amplitude and loading on impact energy were analyzed by theoretical method. Then a full-scale drilling experiment was conducted to study the rock-drilling efficiency. The results are as follows: the optimal frequency is higher than the resonance frequency of the rock. The impact energy increase with the dynamic loading amplitude. The penetration rate at dynamic loading amplitude of 4 KN (0.13137 mm/s) is 38.7% higher than that of 2 KN (0.09473mm/s). When the impact frequency is lower than150 Hz, the rock-drilling efficiency increases with the impact frequency and dynamic loading amplitude. The penetration rate is 0.1051 mm/s at impact frequency of 150 Hz, which is 29.8% higher than that of 10 Hz. The impact energy and penetration rate at square loading waveform are the largest. The impact energy per second at loading waveform of square, sine and triangular is 19.6 J, 12 J and 7.91 J respectively when the impact frequency is set to optimal frequency of impact energy. This study provides a theoretical guidance for the optimization design of vibro-impact drilling technology.


2018 ◽  
Vol 64 (1) ◽  
pp. 77-85 ◽  
Author(s):  
David Bellar ◽  
Cory Etheredge ◽  
Lawrence W. Judge

Abstract Suspension exercise systems are being used in strength and conditioning facilities, fitness centers, rehabilitation centers and home gyms. Though some evidence exists regarding the impact of training with these systems, more work is needed for a better understanding. The purpose of the present investigation was to examine the acute effects of an exercise session with 2 (hands only) and 4 straps (hands and feet) in the push-up exercise compared to a work-matched bench press exercise session. The participants for this repeated measures, cross-over investigation were 18 healthy college-aged males (age: 24.8 ± 3.5 yrs, body mass: 81.8 ± 7.8 kg, body height: 178.9 ± 4.5 cm). The conditions were 6 sets of 10 repetitions of suspension push-ups using two straps (DUAL) for the hands, fours straps (QUAD) for hands and feet and a traditional bench press exercise matched to the average resistance during the suspension push-up. The participants performed all repetitions at a controlled cadence. Expired gases, and heart rate were monitored continuously during the exercise session. Pre and post exercise saliva samples were collected to quantify changes in testosterone and cortisol. Upper body isometric strength tests ( UBIST) were performed (Post, 1 hr, 24 hr, 48 hr) to evaluate changes in force production during recovery. Data analysis via repeated measures ANOVA revealed a significant trend for increased oxygen consumption in the QUAD condition compared to the bench press (p = 0.019). Additionally, both suspension conditions resulted in a reduced respiratory exchange ratio as compared to the bench press (p < 0.05). A significant main effect was noted for time in all conditions regarding isometric strength (p < 0.001), but no differences between conditions were revealed. Testosterone and cortisol responses did not differ between conditions. Based upon these data, it appears that when matched for work, suspension exercise results in equivalent reductions in muscle force, but greater oxygen consumption compared to isotonic exercise.


Kinesiology ◽  
2021 ◽  
Vol 53 (1) ◽  
pp. 56-64
Author(s):  
Asier Los Arcos ◽  
Asier Gonzalez-Artetxe

The aim of this study was to look into the alleged impact of the physical fitness performance of elite junior soccer players on the professional career according to playing position. The physical tests (sprint test, countermovement jump [CMJ], and maximal aerobic speed [MAS]) performed by 165 players enrolled in the junior team of a Spanish 1st Division club (1998-2010) were evaluated. Players were classified as those who were promoted to the reserve team (Reserve Team) and those who were not (non-Reserve Team), and as those who were promoted to the Spanish 1st/2nd Divisions (PFL) and those who were not (NPFL) until the 2020-2021 season. Overall, no significant differences (p&gt;.05) were found between the Reserve Team and non-Reserve Team or between the PFL and NPFL players in neuromuscular performance. Aerobic fitness was greater (p&lt;.05; ES = .79 ± .60 , moderate; mean difference = 3.0%) for the Reserve Team lateral midfielders in comparison to that for the non-Reserve Team. The results suggest that the impact of physical fitness on the promotion of elite junior soccer players is limited.


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