The purposes of this study were to examine the effect of ballistic concentric-only half-squats (COHS) on subsequent squat-jump (SJ) performances at various rest intervals and to examine the relationships between changes in SJ performance and bilateral symmetry at peak performance. Thirteen resistance-trained men performed an SJ immediately and every minute up to 10 min on dual force plates after 2 ballistic COHS repetitions at 90% of their 1-repetition-maximum COHS. SJ peak force, peak power, net impulse, and rate of force development (RFD) were compared using a series of 1-way repeated-measures ANOVAs. The percent change in performance at which peak performance occurred for each variable was correlated with the symmetry index scores at the corresponding time point using Pearson correlation coefficients. Statistical differences in peak power (P = .031) existed between rest intervals; however, no statistically significant pairwise comparisons were present (P > .05). No statistical differences in peak force (P = .201), net impulse (P = .064), and RFD (P = .477) were present between rest intervals. The relationships between changes in SJ performance and bilateral symmetry after the rest interval that produced the greatest performance for peak force (r = .300, P = .319), peak power (r = –.041, P = .894), net impulse (r = –.028, P = .927), and RFD (r = –.434, P = .138) were not statistically significant. Ballistic COHS may enhance SJ performance; however, the changes in performance were not related to bilateral symmetry.

Objectives: The purpose of this study was to examine the relationship of velocities in the back squat between one repetition maximum (1RM) and submaximally loaded repetition maximum (RM) conditions, specifically in regard to what has been described as the minimal velocity threshold (MVT). The MVT describes a minimum concentric velocity that an individual must reach or surpass in order to successfully complete a repetition. Design: To test the presence of a MVT, participants were tested for 1RM and RM back squat ability. The mean concentric veloci ties (MCV) of the last successful repetition of each condition were then compared. Methods: Fourteen male participants familiar with the back squat volunteered to participate in the current study (age = 25.0 y ± 2.6, height = 178.9 cm ± 8.1, body mass = 88.2 kg ± 15.8). The mean concentric velocity (MCV) during the last successful repetition from each testing condition was considered for the comparison. Results: Results indicated a non-significant negative relationship of MCV between the 1RM and RM conditions (r = -0.135), no statistical difference between testing conditions (p = 0.266), with a small-to-moderate effect size (d = 0.468). Conclusions: The results of this study suggest that MVT should be further investigated to enhance its use in the practical setting. Additionally, coaches considering using a velocity-based approach for testing athletes should use data from either 1RM or RM conditions, but not both interchangeably. Coaches should be cautious when considering group averages or comparing velocity data between athletes, which may not be appropriate based on our results.

The purpose of this study was to develop a measurement procedure for the Maltese cross performed on still rings. Sixteen elite/international gymnasts participated. Two small force platforms (FPs) interfaced to a portable data logger (100 Hz sampling rate) were placed under the gymnasts’ hands in a simulated Maltese position (i.e., prone). Gymnasts attempted to rise a few centimeters to a Maltese position while vertical ground reaction forces were recorded bilaterally. Results indicated that the FPs had sufficient fidelity to differentiate gymnasts’ abilities to perform a Maltese. This method may serve to gauge the preparedness of male gymnasts performing this important skill.

Abstract available in the Medicine and Sciences in Sports and Exercise.

PURPOSE: The purpose of the study was to examine the relationship between bat swing velocity and lower extremity strength and power in NCAA Division-I softball athletes. METHODS: Twenty-nine softball athletes (age = 19.8 ± 1.3 years, height = 167.9 ± 6.8 cm, mass = 76.4 ± 18.1 kg) participated in the study. Athletes were tested on unloaded and loaded (20kg) squat and countermovement jump peak force, peak power, and jump height performed on a force platform sampling at 1000Hz. During practice, athletes were tested on swing velocity using a timing gate system. Pearson-product moment zero-order correlations were calculated between bat swing velocity and lower extremity strength and power. Statistical significance was set at p≤0.05. RESULTS: Moderate to strong relationships were observed between swing velocity and peak force at all conditions: SJ 0kg (r= 0.51, p= 0.005), SJ 20kg (r= 0.50, p= 0.006), CMJ 0kg (r= 0.44, p= 0.016), CMJ 20kg (r= 0.43, p= 0.022). Additionally, relationships were observed between swing velocity and peak power at all conditions: SJ 0kg (r= 0.45, p= 0.015), SJ 20kg (r= 0.40, p= 0.031), CMJ 0kg (r= 0.53, p= 0.003), CMJ 20kg (r= 0.45, p= 0.015). No statistically significant relationships were observed between swing velocity and jump height. CONCLUSIONS: Swing velocity was related to lower extremity force and power variables. Considering the known effects of strength training on lower extremity strength and power production, these results provide background for inclusion of lower extremity strength training for the development of swing velocity in NCAA Division-I softball athletes.

Planning training programs for strength–power track and field athletes require an understanding of both training principles and training theory. The training principles are overload, variation, and specificity. Each of these principles must be incorporated into an appropriate system of training. Conceptually, periodization embraces training principles and offers advantages in planning, allowing for logical integration and manipulation of training variables such as exercise selection, intensification, and volume factors. The adaptation and progress of the athlete is to a large extent directly related to the ability of the coach/athlete to create and carry an efficient and efficacious training process. This ability includes: an understanding of how exercises affect physiological and performance adaptation (i.e., maximum force, rate of force development, power, etc.), how to optimize transfer of training effect ensuring that training exercises have maximum potential for carryover to performance, and how to implement programs with variations at appropriate levels (macro, meso, and micro) such that fatigue management is enhanced and performance progress is optimized.

No description available.

No description available.

Complex training is commonly utilized in an attempt to facilitate peak power production and Rate of Force Development (RFD) via Post Activation Potentiation (PAP). This research compared the effects of six weeks of; resistance (RT), plyometric (PT), and complex training (CT) upon the relationship between peak ground reaction forces (pGRF), jump performance, and strength. Thirty-four recreationally trained college aged males (21.44 ± 3.32 years) were trained using 1 of 3 methods; resistance (RT; n = 13; 180.14 ± 4.75 cm; 83.85 ± 20.54 kg), plyometric (PT; n = 11; 181.41 ± 7.97 cm; 81.25 ± 10.43 kg), or complex training (CT; n = 10; 185.17 ± 5.56 cm; 87.54 ± 9.04 kg) twice a week for 6 weeks. Participants were tested pre (W1) and post (W9) training to assess vertical jump height (CMVJ; cm), broad jump distance (BDJ; cm), pGRF (N), and multiple 1RM (kg) strength measures. Correlation matrices calculated on % change scores for performance measures from W1 to W9 between conditions, revealed significant positive and negative correlations (r range = -.730 through .996; p < .01* and p < .05**). The greatest total of significant correlation coefficients (r) for % change was seen for the RT group. Differences in training adaptations between groups at both the muscular and neuromuscular level may account for the differences seen.

Countermovement vertical jump (CMVJ) performance may be acutely facilitated via potentiation (PAP) due to central and peripheral factors. PURPOSE: To investigate the effects of two methods of PAP in trained weightlifters (n=16); group 1: stronger (n=7) and group 2: weaker (n=9) upon unweighted countermovement jumps (CMVJs) over a 15 minute time period. METHODS: A series of maximal unweighted CMVJs were performed prior to, then at, 30, 60, 120, 180, 300, 480, 660, 780, and 900 seconds following two conditions: isometric mid-thigh clean pulls (C1) and dynamic mid-thigh clean pulls (C2). Dependent variables included, jump height (JH, cm), peak power (PP, W), peak velocity (PV, m·s-1), and peak force (PF, N). RESULTS: A series of repeated measures ANOVA: conditions (2); time points (10); groups (2) were performed on JH, PP, PV, and PF (p>.05). Significant main effects for JH existed by condition (C1>C2) (p=.001, ES=.571, 1-β=.979, mean diff=.053cm), group (G1>G2) (p=.018, ES=.339, 1-β=.702, mean diff=.053), and time (60s>900s, 120s>900s, 180s>900s) (p=.014, ES=.148, 1-β=.910).Within subjects main effects for JH were seen for the stronger group for JH by condition (C1>C2) (p=.055, ES=.757, 1-β=.947, mean diff=.053cm), and weaker group by condition (C1>C2) (p=.025, ES=.487, 1-β=.676, mean diff=.054cm). Significant main effects existed for PP by condition (C1>C2) (p=.000, ES=.631, 1-β=.995, mean diff=427.9W), group (G1>G2) (p=.008, ES=.405, 1-β=.819, mean diff=1660.1W), and time (60s>480s, 60s>660s, 60s>780s, 60s>900s>120s>900s, 180s>480s, 180s>660s, 180s>780s) (p=.000, ES=.355, 1-β=1.00, mean diff=240.1W ).Within subjects main effects for PP were seen for the stronger group for condition (C1>C2) (p=.055, ES=.761, 1-β=.951, mean diff=516.8W), and time (120s>900s) (p=.000, ES=.471,1-β=.999, mean diff=319.5W). In the weaker group; significant main effects by condition (C1>C2) (p=.025, ES=.485, 1-β=.672, mean diff=339.1W) and time (120s>900s, 180s>480s, 180s>900s, 300s>900s) (p=.003, ES=.281, 1-β=.963, mean diff=319.5W). Significant main effects were seen for jump PV by condition (C1>C2) (p=.001, ES=.536,1-β=.962, mean diff=.177 m·s-1), group (G1>G2) (p=.022, ES=.320, 1-β=.665, mean diff=.298m/s) and by time (60s>900s, 120s>900s, 180s>900s) (p=.016, ES=.145, 1-β=.904). Within subjects main effects for jump PV in the stronger group by condition (C1>C2) (p=.007, ES=.727, 1-β=.911, mean diff=.165m/s), and time (120s>900s) (p=.036, ES=.269, 1-β=.840, mean diff=.073 m·s-1). In the weaker group there were significant main effects for jump PV by condition (C1>C2) (p=.028, ES=.474, 1-β=.654, mean diff=.188 m·s-1). A significant main effect for jump PF by group (G1>G2) (p=.014, ES=.363, 1-β=.747, mean diff=647.0N) and time (60s>baseline) (p=.05, ES=.122, 1-β=.824, mean diff=71.0N) was seen. Within subjects, a significant main effect for jump PF in the weaker group by time (60s>780s) (p=.012, ES=.247, 1-β=.919). There were no significant interactions for any of the dependent variables (p >.05). CONCLUSION: Isometric mid-thigh clean pulls appear to have a greater potentiating effect than dynamic mid-thigh pulls on PP and PV during subsequent CMVJ0’s, and stronger weightlifters tend to have a more favorable response to both conditions. PRACTICAL APPLICATION: Whole-body isometric movements may be a more effective at eliciting a potentiation response than dynamic movements in strength and power athletes.