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Dajo Sanders, Mathieu Heijboer, Ibrahim Akubat, Kenneth Meijer and Matthijs K. Hesselink

Purpose:

To assess if short-duration (5 to ~300 s) high-power performance can accurately be predicted using the anaerobic power reserve (APR) model in professional cyclists.

Methods:

Data from 4 professional cyclists from a World Tour cycling team were used. Using the maximal aerobic power, sprint peak power output, and an exponential constant describing the decrement in power over time, a power-duration relationship was established for each participant. To test the predictive accuracy of the model, several all-out field trials of different durations were performed by each cyclist. The power output achieved during the all-out trials was compared with the predicted power output by the APR model.

Results:

The power output predicted by the model showed very large to nearly perfect correlations to the actual power output obtained during the all-out trials for each cyclist (r = .88 ± .21, .92 ± .17, .95 ± .13, and .97 ± .09). Power output during the all-out trials remained within an average of 6.6% (53 W) of the predicted power output by the model.

Conclusions:

This preliminary pilot study presents 4 case studies on the applicability of the APR model in professional cyclists using a field-based approach. The decrement in all-out performance during high-intensity exercise seems to conform to a general relationship with a single exponential-decay model describing the decrement in power vs increasing duration. These results are in line with previous studies using the APR model to predict performance during brief all-out trials. Future research should evaluate the APR model with a larger sample size of elite cyclists.

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Gemma N. Parry, Lee C. Herrington and Ian G. Horsley

Upper-limb muscular power output is a fundamental and highly desirable characteristic across a number of explosive short-duration sports. 1 , 2 Because upper-limb muscle power output is considered to be a principle movement skill and a key aspect of sporting performance and athletic ability, it is

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Erin E. Sutton, M. Regina Coll and Patricia A. Deuster

Acute tyrosine ingestion is thought to improve aerobic endurance, muscle strength and endurance, and anaerobic power of men undergoing severe physiologic stress. In a double-blind, crossover study, 20 men (32 ± 1 y old) underwent 2 loadcarriage treadmill sessions, 1 after taking tyrosine (150 mg/kg L-crystalline tyrosine) and 1 after taking placebo. Tyrosine dosage was based on subject weight and ingested 30 min before load carriage. A physical performance battery was administered after the load carriage: maximal and submaximal handgrip, pull-ups, and stair stepping with weight. Total time on treadmill was not significantly lengthened with ingestion of tyrosine (118.9 ± 1.4 min) as compared with placebo (119.2 ± 1.2 min). Total power for stair stepping (tyrosine 223 ± 8 watts, placebo 216 ± 9 watts) and muscle strength and endurance (handgrip) was not significantly improved by tyrosine ingestion. The results indicate that acute ingestion of tyrosine by healthy men has no measurable effect on endurance, muscle strength, or anaerobic power.

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Christos K. Argus, Nicholas D. Gill, Justin W.L. Keogh, Michael R. McGuigan and Will G. Hopkins

Purpose:

There is little literature comparing contrast training programs typically performed by team-sport athletes within a competitive phase. We compared the effects of two contrast training programs on a range of measures in high-level rugby union players during the competition season.

Methods:

The programs consisted of a higher volume-load (strength-power) or lower volume-load (speed-power) resistance training; each included a tapering of loading (higher force early in the week, higher velocity later in the week) and was performed twice a week for 4 wk. Eighteen players were assessed for peak power during a bodyweight countermovement jump (BWCMJ), bodyweight squat jump (BWSJ), 50 kg countermovement jump (50CMJ), 50 kg squat jump (50SJ), broad jump (BJ), and reactive strength index (RSI; jump height divided by contact time during a depth jump). Players were then randomized to either training group and were reassessed following the intervention. Inferences were based on uncertainty in outcomes relative to thresholds for standardized changes.

Results:

There were small between-group differences in favor of strength-power training for mean changes in the 50CMJ (8%; 90% confidence limits, ±8%), 50SJ (8%; ±10%), and BJ (2%; ±3%). Differences between groups for BWCMJ, BWSJ, and reactive strength index were unclear. For most measures there were smaller individual differences in changes with strength-power training.

Conclusion:

Our findings suggest that high-level rugby union athletes should be exposed to higher volume-load contrast training which includes one heavy lifting session each week for larger and more uniform adaptation to occur in explosive power throughout a competitive phase of the season.

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Jeffrey M. McBride, Tyler J. Kirby, Tracie L. Haines and Jared Skinner

Purpose:

The purpose of the current investigation was to determine the relationship between relative net vertical impulse (net vertical impulse (VI)) and jump height in the jump squat (JS) going to different squat depths and utilizing various loads.

Methods:

Ten males with two years of jumping experience participated in this investigation (Age: 21.8 ± 1.9 y; Height: 176.9 ± 5.2 cm; Body Mass: 79.0 ± 7.1 kg, 1RM: 131.8 ± 29.5 kg, 1RM/BM: 1.66 ± 0.27). Subjects performed a series of static jumps (SJS) and countermovement jumps (CMJJS) with various loads (Body Mass, 20% of 1RM, 40% of 1RM) in a randomized fashion to a depth of 0.15, 0.30, 0.45, 0.60, and 0.75 m and a self-selected depth. During the concentric phase of each JS, peak force (PF), peak power (PP), jump height (JH) and relative VI were recorded and analyzed.

Results:

Increasing squat depth corresponded to a decrease in PF and an increase in JH, relative VI for both SJS and CMJJS during all loads. Across all squat depths and loading conditions relative VI was statistically significantly correlated to JH in the SJS (r = .8956, P < .0001, power = 1.000) and CMJJS (r = .6007, P < .0001, power = 1.000). Across all squat depths and loading conditions PF was statistically nonsignificantly correlated to JH in the SJS (r = –0.1010, P = .2095, power = 0.2401) and CMJJS (r = –0.0594, P = .4527, power = 0.1131). Across all squat depths and loading conditions peak power (PP) was significantly correlated with JH during both the SJS (r = .6605, P < .0001, power = 1.000) and the CMJJS (r = .6631, P < .0001, power = 1.000). PP was statistically significantly higher at BM in comparison with 20% of 1RM and 40% of 1RM in the SJS and CMJJS across all squat depths.

Conclusions:

Results indicate that relative VI and PP can be used to predict JS performance, regardless of squat depth and loading condition. However, relative VI may be the best predictor of JS performance with PF being the worst predictor of JS performance.

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M. Travis Byrd, Jonathan Robert Switalla, Joel E. Eastman, Brian J. Wallace, Jody L. Clasey and Haley C. Bergstrom

The critical-power (CP) (and critical force) test of Monod and Scherrer involved dynamic, intermittent, static, and continuous muscle actions for isolated movements of synergic muscle groups including the forearm flexors, forearm extensors, and leg flexors. 1 This test involves local muscle work

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Mário A.M. Simim, Gustavo R. da Mota, Moacir Marocolo, Bruno V.C. da Silva, Marco Túlio de Mello and Paul S. Bradley

their physical capacity, it is very difficult to objectively verify fatigue using time-motion analysis alone. Fatigue in AS might also be highly complex, and thus, time-motion characteristics and game-induced decrements in neuromuscular measures (i.e., muscular endurance and power) must also be

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Michal Wilk, Michal Krzysztofik, Milosz Drozd and Adam Zajac

The ability to generate power is one of the most significant factors that determine performance in numerous sport disciplines. Power output can be described by the relationship between the force generated by the muscles and movement velocity. 1 Resistance training is one of the key tools used in

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Taylor K. Dinyer, M. Travis Byrd, Ashley N. Vesotsky, Pasquale J. Succi and Haley C. Bergstrom

The critical power (CP) model was originally developed as a 2-parameter linear model to examine the relationship between total work and time to exhaustion ( T lim ) for dynamic, continuous isometric, and intermittent isometric contractions of a muscle or local muscle group (less than one-third the

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Brian A. Eiler, Rosemary Al-Kire, Patrick C. Doyle and Heidi A. Wayment

surprising given that sexual violence is often committed by individuals in positions of power and authority across a wide variety of contexts (e.g.,  Brackenridge, 2001 ; Watts & Zimmerman, 2002 ). Unfortunately, literature on athletes’ psychosocial experiences and reactions to abuse (e