Peter D. Mundy

Power and impulse applied during push press exercise

Abstract Lake, JP, Mundy, PD, and Comfort, P. Power and impulse applied during push press exercise. J Strength Cond Res 28(9): 2552–2559, 2014—The aim of this study was to quantify the load, which maximized peak and mean power, and impulse applied to these loads, during the push press and to compare them to equivalent jump squat data. Resistance-trained men performed 2 push press (n = 17; age: 25.4 ± 7.4 years; height: 183.4 ± 5 cm; body mass: 87 ± 15.6 kg) and jump squat (n = 8 of original 17; age: 28.7 ± 8.1 years; height: 184.3 ± 5.5 cm; mass: 98 ± 5.3 kg) singles with 10–90% of their push press and back squat 1 repetition maximum (1RM), respectively, in 10% 1RM increments while standing on a force platform. Push press peak and mean power was maximized with 75.3 ± 16.4 and 64.7 ± 20% 1RM, respectively, and impulses applied to these loads were 243 ± 29 N·s and 231 ± 36 N·s. Increasing and decreasing load, from the load that maximized peak and mean power, by 10 and 20% 1RM reduced peak and mean power by 6–15% (p ⩽ 0.05). Push press and jump squat maximum peak power (7%, p = 0.08) and the impulse that was applied to the load that maximized peak (8%, p = 0.17) and mean (13%, p = 0.91) power were not significantly different, but push press maximum mean power was significantly greater than the jump squat equivalent (∼9.5%, p = 0.03). The mechanical demand of the push press is comparable with the jump squat and could provide a time-efficient combination of lower-body power and upper-body and trunk strength training.

Carbohydrate Mouth Rinse Improves Morning High-Intensity Exercise Performance

Abstract Oral carbohydrate (CHO) rinsing has been demonstrated to provide beneficial effects on exercise performance of durations of up to one hour. The aim of the present study was to investigate the effects of CHO mouth rinsing on morning high-intensity exercise performance. Following institutional ethical approval and familiarisation, 12 healthy males (mean ± SD age: 23 ± 3 years, height: 175.5 ± 7.4 cm, body mass: 75.4 ± 7.5 kg) participated in this study. Countermovement jump (CMJ) height, isometric mid-thigh pull peak force, 10 m sprint time and bench press and back squat repetitions to failure were assessed following CHO and placebo (PLA) rinsing or a control condition (CON). All testing took place at 07:30 following an 11 hour overnight fast. Performance of CMJ height (CHO: 39 ± 7 cm; PLA: 38 ± 7 cm; CON: 36 ± 6 cm; P = .003,  = 0.40), 10 m sprint time (CHO: 1.78 ± 0.07 s; PLA: 1.81 ± 0.07 s; CON: 1.85 ± 0.05 s; P = .001,  = 0.47), the number of bench press (CHO: 25 ± 3; PLA: 24 ± 4; CON: 22 ± 4; P < .001,  = 0.55) and squat (CHO: 31 ± 4; PLA: 29 ± 5; CON: 26 ± 6; P < .001,  = 0.70) repetitions and mean felt arousal (CHO: 5 ± 1; PLA: 4 ± 0; CON: 4 ± 0; P = .009,  = 0.25) improved following CHO rinsing. However, isometric mid-thigh pull peak force was unchanged (CHO: 2262 ± 288 N; PLA: 2236 ± 354 N; CON: 2212 ± 321 N; P = .368,  = 0.08). These results suggest that oral CHO rinsing solution significantly improved the morning performance of CMJ height, 10 m sprint times, bench press and squat repetitions to failure and felt arousal, although peak force during an isometric mid-thigh pull, rating of perceived exertion and heart rate were unaffected.

Support leg action can contribute to maximal instep soccer kick performance: an intervention study

ABSTRACT This investigation assessed whether a Technique Refinement Intervention designed to produce pronounced vertical hip displacement during the kicking stride could improve maximal instep kick performance. Nine skilled players (age 23.7 ± 3.8 years, height 1.82 ± 0.06 m, body mass 78.5 ± 6.1 kg, experience 14.7 ± 3.8 years; mean ± SD) performed 10 kicking trials prior to (NORM) and following the intervention (INT). Ground reaction force (1000 Hz) and three-dimensional motion analysis (250 Hz) data were used to calculate lower limb kinetic and kinematic variables. Paired t-tests and statistical parametric mapping examined differences between the two kicking techniques across the entire kicking motion. Peak ball velocities (26.3 ± 2.1 m · s−1 vs 25.1 ± 1.5 m · s−1) and vertical displacements of the kicking leg hip joint centre (0.041 ± 0.012 m vs 0.028 ± 0.011 m) were significantly larger (P < 0.025) when performed following INT. Further, various significant changes in support and kicking leg dynamics contributed to a significantly faster kicking knee extension angular velocity through ball contact following INT (70–100% of total kicking motion, P < 0.003). Maximal instep kick performance was enhanced following INT, and the mechanisms presented are indicative of greater passive power flow to the kicking limb during the kicking stride.

The effects of barbell load on countermovement vertical jump power and net impulse

ABSTRACT The aim of this study was to examine the effects of barbell load on countermovement vertical jump (CMJ) power and net impulse within a theoretically valid framework, cognisant of the underpinning force, temporal, and spatial components. A total of 24 resistance-trained rugby union athletes (average ± SD: age: 23.1 ± 3.4 years; height: 1.83 ± 0.05 m; body mass (BM): 91.3 ± 10.5 kg) performed maximal CMJ under 5 experimental conditions in a randomised, counterbalanced order: unloaded, and with additional loads of 25%, 50%, 75%, and 100% of BM. Peak power and average power were maximised during the unloaded condition, both decreasing significantly (P < 0.05) as load increased. Net impulse was maximised with 75% of BM, which was significantly greater (P < 0.05) than the unloaded and 100% of BM conditions. Net mean force and mean velocity were maximised during the unloaded condition and decreased significantly (P < 0.05) as load increased, whereas phase duration increased significantly (P < 0.05) as load increased. As such, the interaction between barbell load and the underpinning force, time, and displacement components should be considered by strength and conditioning coaches when prescribing barbell loads.

Agreement between the force platform method and the combined method measurements of power output during the loaded countermovement jump

Abstract There are two perceived criterion methods for measuring power output during the loaded countermovement jump (CMJ): the force platform method and the combined method (force platform + optoelectronic motion capture system). Therefore, the primary aim of the present study was to assess agreement between the force platform method and the combined method measurements of peak power and mean power output during the CMJ across a spectrum of loads. Forty resistance-trained team sport athletes performed maximal effort CMJ with additional loads of 0 (body mass only), 25, 50, 75 and 100% of body mass (BM). Bias was present for peak velocity, mean velocity, peak power and mean power at all loads investigated, and present for mean force up to 75% of BM. Peak velocity, mean velocity, peak power and mean power 95% ratio limits of agreement were clinically unacceptable at all loads investigated. The 95% ratio limits of agreement were widest at 0% of BM and decreased linearly as load increased. Therefore, the force platform method and the combined method cannot be used interchangeably for measuring power output during the loaded CMJ. As such, if power output is to be meaningfully investigated, a standardised method must be adopted.

The effect of barbell load on vertical jump landing force-time characteristics

The aim of this study was to quantify the effect that barbell load has on the jump height and force-time characteristics of the countermovement jump (CMJ). Fifteen strengthtrained men (mean ± SD: age 23 ± 2 years, mass 84.9 ± 8.1 kg, height 1.80 ± 0.05 m) performed three CMJ with no additional load, and with barbell loads of 25%, 50%, 75%, and 100% of body mass on two force plates recording at 1000 Hz. Propulsion and landing force-time characteristics were obtained from force-time data and compared using analysis of variance and effect sizes. Jump height decreased significantly as load increased (26 to 71%, d = 1.80 to 6.87). During propulsion, impulse increased with load up to 75% of body mass (6 to 9%, d = 0.71 to 1.08), mean net force decreased (10 to 43%, d = 0.50 to 2.45) and time increased (13 to 50%, d = 0.70 to 2.57). During landing, impulse increased as load increased up to 75% of body mass (5 to 12%, d = 0.54 to 1.01), mean net force decreased (13 to 38%, d = 0.41 to 1.24), and time increased (20 to 47%, d = 0.65 to 1.47). Adding barbell load to CMJ significantly decreases CMJ height. Furthermore, CMJ with additional barbell load increases landing phase impulse. However, while mean net force decreases as barbell load increases, landing time increases so that jumpers are exposed to mechanical load for longer. Practitioners should exercise caution when implementing loaded CMJ to assess their athletes.

Force-time Characteristics of the Countermovement Jump: Analyzing the Curve in Excel

ABSTRACT INCREASED POPULARITY IN THE UTILIZATION OF FORCE PLATES TO MEASURE COUNTERMOVEMENT JUMPS (CMJS) FOR PERFORMANCE MONITORING WARRANTS THE NEED FOR STRENGTH AND CONDITIONING COACHES AND SPORT SCIENTISTS TO BETTER UNDERSTAND ITS FORCE-TIME CHARACTERISTICS AND THE CALCULATION OF ITS ASSOCIATED VARIABLES. THIS ARTICLE AIMS TO PROVIDE INFORMATION ON HOW TO UNDERSTAND AND ANALYZE THE FORCE-TIME CURVE OF CMJS IN MICROSOFT EXCEL, THUS PROVIDING PRACTITIONERS AN INEXPENSIVE AND ACCESSIBLE ALTERNATIVE TO READILY AVAILABLE SOFTWARE ON THE MARKET.

Coffee and Caffeine Ingestion Have Little Effect on Repeated Sprint Cycling in Relatively Untrained Males

The present study investigated the effect of ingesting caffeine-dose-matched anhydrous caffeine or coffee on the performance of repeated sprints. Twelve recreationally active males (mean ± SD age: 22 ± 2 years, height: 1.78 ± 0.07 m, body mass: 81 ± 16 kg) completed eighteen 4 s sprints with 116 s recovery on a cycle ergometer on four separate occasions in a double-blind, randomised, counterbalanced crossover design. Participants ingested either 3 mg·kg−1 of caffeine (CAF), 0.09 g·kg−1 coffee, which provided 3 mg·kg−1 of caffeine (COF), a taste-matched placebo beverage (PLA), or a control condition (CON) 45 min prior to commencing the exercise protocol. Peak and mean power output and rating of perceived exertion (RPE) were recorded for each sprint. There were no significant differences in peak power output (CAF: 949 ± 199 W, COF: 949 ± 174 W, PLA: 971 ± 149 W and CON: 975 ± 170 W; p = 0.872; ηP2 = 0.02) or mean power output (CAF: 873 ± 172 W, COF: 862 ± 44 W, PLA: 887 ± 119 W and CON: 892 ± 143 W; p = 0.819; ηP2 = 0.03) between experimental conditions. Mean RPE was similar for all trials (CAF: 11 ± 2, COF: 11 ± 2, PLA: 11 ± 2 and CON: 11 ± 2; p = 0.927; ηP2 = 0.01). Neither the ingestion of COF or CAF improved repeated sprint cycling performance in relatively untrained males.

Do the peak and mean force methods of assessing vertical jump force asymmetry agree

Abstract The aim of this study was to assess agreement between peak and mean force methods of quantifying force asymmetry during the countermovement jump (CMJ). Forty-five men performed four CMJ with each foot on one of two force plates recording at 1,000 Hz. Peak and mean were obtained from both sides during the braking and propulsion phases. The dominant side was obtained for the braking and propulsion phase as the side with the largest peak or mean force and agreement was assessed using percentage agreement and the kappa coefficient. Braking phase peak and mean force methods demonstrated a percentage agreement of 84% and a kappa value of 0.67 (95% confidence limits: 0.45–0.90), indicating substantial agreement. Propulsion phase peak and mean force methods demonstrated a percentage agreement of 87% and a kappa value of 0.72 (95% confidence limits: 0.51–0.93), indicating substantial agreement. While agreement was substantial, side-to-side differences were not reflected equally when peak and mean force methods of assessing CMJ asymmetry were used. These methods should not be used interchangeably, but rather a combined approach should be used where practitioners consider both peak and mean force to obtain the fullest picture of athlete asymmetry.