Relative Peak Power Research Articles

Peak power in the hexagonal barbell jump squat and its relationship to jump performance and acceleration in elite rugby union players.

Recent research suggests that jump squats with a loaded hexagonal barbell are superior for peak power production to comparable loads in a traditional barbell loaded jump squat. The aim of this study was to investigate the relationship between relative peak power output during performance of the hexagonal barbell jump squat (HBJS), countermovement jump (CMJ) height, and linear acceleration speed in rugby union players. Seventeen professional rugby union players performed 10- and 20-m sprints, followed by a set of 3 unloaded CMJs and a set of 3 HBJS at a previously determined optimal load corresponding with peak power output. The relationship between HBJS relative peak power output, 10- and 20-m sprint time, and CMJ height was investigated using correlation analysis. The contribution of HBJS relative peak power output and CMJ height to 10- and 20-m sprint time was investigated using standard multiple regression. Strong, significant, inverse correlations were observed between HBJS relative peak power output, 10-m sprint time (r = -0.70, p < 0.01), and 20-m sprint time (r = -0.75, p < 0.01). A strong, significant, positive correlation was observed between HBJS relative peak power output and CMJ height (r = 0.80, p < 0.01). Together, HBJS relative peak power output and CMJ height explained 46% of the variance in 10-m sprint time while explaining 59% of the variance in 20-m sprint time. The findings of the current study demonstrate a significant relationship between relative peak power in the HBJS and athletic performance as quantified by CMJ height and 10- and 20-m sprint time.

Effects of Age and Sex on Muscle Function during Isovelocity Contractions.

PURPOSE: To assess the effect of age and sex on absolute and relative knee extensor peak torque (PT), power (PW), and time to peak torque (TTP) at multiple velocities. METHODS: 61 women and 87 men completed 3 maximal knee extensions at 60, 120, and 180°/s on an isokinetic dynamometer. Data were analyzed as absolute values and relative to FFM. Volunteers were grouped by sex and age (YW=young women (20 yr); YM=young men (21 yr); OW=old women (71 yr); OM=old men (73 yr)). FFM was estimated with bio-impedance. ANOVAs were conducted to locate differences between groups. RESULTS: Absolute and relative PT (60 °/s) were different between sex (absolute PT: YM=236.3 vs. YW=148.8; OM=137.2 vs. OW=85.4 Nm) and age groups (YW>OW; YM>OM). Absolute and relative PT (120 °/s) were different between sex (absolute PT: YM=187.0 vs. YW=117.0; OM=108.1 vs. OW=65.9 Nm) and age groups (YW>OW; YM>OM). Absolute and relative PT (180 °/s) were different between sex (absolute PT: YM=155.8 vs. YW=97.5; OM=90.7 vs. OW=56.1 Nm) and age groups (YW>OW; YM>OM). Absolute and relative PW (60 °/s) were different between sex (absolute PW: YM=157.6 vs. YW=101.2; OM=91.1 vs. OW=57.4 W) and age groups (YW>OW; YM>OM). Absolute and relative PW (120 °/s) were different between sex (absolute PW: YM=256.3 vs. YW=159.9; OM=150.2 vs. OW=89.2 W) and age groups (YW>OW; YM>OM). Absolute and relative PW (180 °/s) were different between sex (absolute PW: YM=311.2 vs. YW=189.2; OM=171.7 vs. OW=102.5 W) and age groups (YW>OW; YM>OM). Absolute TTP (60 °/s) was not different between sex (absolute TTP: YM=0.27 vs. YW=0.37; OM=0.31 vs. OW=0.27 s) and age groups. Relative TTP was different between sex (YM=0.004 vs. YW=0.006; OM=0.005 vs. OW=0.007 s) but not age groups. Absolute TTP (120 °/s) was not different between sex (absolute TTP: YM=0.18 vs. YW=0.21; OM=0.18 vs. OW=0.19 s) and age groups. Relative TTP was different between sex (YM=0.0008 vs. YW=0.001; OM=0.003 vs. OW=0.004 s) but not age groups. Absolute TTP (180 °/s) was not different between sex (absolute TTP: YM=0.13 vs. YW=0.13; OM=0.11 vs. OW=0.13 s) and age groups. Relative TTP was different between sex (YM=0.002 vs. YW=0.003; OM=0.002 vs. OW=0.003 s) but not age groups. CONCLUSION: Older adults had reduced absolute and relative PT and PW compared to young adults. YM had faster relative TTP than YW; and OM had faster relative TTP than OW. Supported by NIH National Center for Complementary and Alternative Medicine (1R15 AT003938-01) and the BU Foundation

Relationship Between Physical Factors and Non-Sport Specific Movement Skills in Australian Taekwondo Athletes

BACKGROUND: Success in many sports is reliant upon unique skill attributes which are difficult to accurately and reliably assess such as balance, timing, and general coordination. Non-sport specific motor test batteries, such as the körperkoordinationstest für kinder (KTK), are gaining prominence for their ability to reliably assess fundamental movement skill attributes. For instance, the KTK discriminates and predicts expertise in gymnasts. However, as skill tests are difficult to validate, one criticism is that results are reliant upon alternative variables, such anthropometric or physiological qualities. Therefore, the KTK may not actually be a valid assessor of skill. A method of critically evaluating these skill tests is to assess their relationship with traditional measures of anthropometry and physiology. PURPOSE: To assess the relationship between physiological and anthropometric qualities and non-sport specific motor skills. METHODS: Twelve Australian national team taekwondo athletes (mean ± SD; age 23.2 ± 3.7 yrs) completed anthropometric, physiological and fundamental motor skill tests. Anthropometry was assessed by body mass (BM), height (Ht), and sum of seven skinfolds (Sum7); physiological assessment included countermovement jump (CMJ), squat jump (SQJ), and a 20m shuttle run (SRun). Fundamental motor skills were assessed by the KTK, a testing battery of 4 non-sports specific tests including: obstacle hopping for height (HopH); backwards balance beam walking (BacBal); sideways jumping, scored for repetitions over 15 sec (SWJ); and moving sideways on platforms, scored for repetitions over 20 sec (MP). RESULTS: Controlling for gender, KTK performance correlated significantly only with CMJ height (r=.76, P<0.05). Further analysis of KTK subtests revealed BacBal performance correlated with SQJ relative peak power (r=.72, P<<0.05) and HopH correlated with BM (r=-.79, P<0.05). CONCLUSION: Findings demonstrate that physiological and anthropometric qualities have a weak association with non-sport specific motor skills in national level athletes. The KTK may be a valid assessment of fundamental movement skills as performance is likely related to non-physiologic and anthropometric attributes such as perceptual expertise.

Effect of 8 weeks of pre-season training on body composition, physical fitness, anaerobic capacity, and isokinetic muscle strength in male and female collegiate taekwondo athletes.

The purpose of the study was to determine the effect of 8 weeks pre-season training on body composition, physical fitness, anaerobic capacity, and isokinetic strength in collegiate taekwondo athletes. Thirty-four collegiate athletes (male: 22, female: 12) participated. Body composition, bone mineral density, physical fitness, anaerobic capacity, and isokinetic muscle strength were tested. After statistical analysis was performed the results indicated that there were significant decreases in body weight, percent body fat, and fat tissue after 8 weeks of pre-season training. Bone mineral density increased significantly only in males. There were significant improvements in the 50 m shuttle run and 20 m multistage endurance run in both males and females. The sit & reach test and standing long jump were not significantly changed after 8 weeks. Relative peak power and anaerobic capacity were significantly improved in males. Significant increases in angular velocity were observed for knee extension at both % BW 60°/sec and 180°/sec in both males and females. A significant increase in angular velocity was seen for right knee flexion at % BW 60°/sec for males, but it decreased at % BW 180°/sec for both males and females. In conclusion, this study suggests that 8 weeks of pre-season training has a positive effect on body composition, physical fitness, anaerobic capacity, isokinetic muscular strength, and endurance. Nevertheless, an exercise approach with the goal of increasing lean tissue, and improving power in knee flexors and flexibility of athletes, should be included in the training program.

Effects of different doses of caffeine on anaerobic exercise in boys.

This study investigated effects of low (1 mg·kg-1), moderate (3 mg·kg-1) and high (5 mg·kg-1) doses of caffeine on anaerobic performance in boys. Twenty-six 8- to 10-year-old boys participated in a double-blind, crossover, counter-balanced study. Boys received in random order a placebo (PL) or anhydrous caffeine: 1 (CAF-1), 3 (CAF-3), or 5 (CAF-5) mg caffeine·kg-1 body mass in cherry flavored Sprite. Sixty minutes following consumption boys performed a static handgrip test and then a 30-s Wingate test. Maximal grip strength (21.5 ± 4.9 & 21.6 ± 4.7 vs. 20.4 ± 4.0 kg) was significantly higher in CAF-5 & CAF-3 vs PL, respectively. Absolute and relative peak power (287 ± 72 vs 281 ± 69 W & 8.0 ± 0.9 vs 7.8 ± 1.0 W·kg-1) were significantly higher in CAF-3 vs PL, respectively. Mean power (153 ± 48 vs 146 ± 43 W) was significantly higher in CAF-5 vs PL, respectively. Peak Wingate HR was significantly higher (189 ± 8 vs 185 ± 9 beats·min-1) in CAF-5 vs PL, respectively. These findings suggest that in boys CAF-1 did not affect performance. During the Wingate test CAF-3 resulted in higher peak power while CAF-5 increased mean power. The significant increase in peak HR following the Wingate test is likely related to greater mean power generated during CAF-5.

Physical Fitness Profile and Differences Between Light, Middle, and Heavy Weight-Class Groups of Japanese Elite Male Wrestlers

.We investigated the physical fitness of Japanese elite male wrestlers and compared results by groupings of weight classes. Twenty-two elite Japanese male wrestlers (light, participants' body weight 59–65 kg, n = 7; middle, 71–88 kg, n = 8; and heavy, 99–122 kg, n = 7) recruited from wrestling squads participating in national training camps participated in this study. The 90-s maximal anaerobic power test (90-MAT) and maximal graded exercise test (MGT) were performed on a cycle ergometer. Relative peak power during the 90-MAT did not differ among groups (light: 9.0 ± 0.4 W·kg−1, middle: 9.3 ± 0.4 W·kg−1, heavy: 9.0 ± 0.5 W·kg−1, p > 0.05), but mean relative power in the heavy group was lower than that in the other groups (heavy: 4.5 ± 0.5 W·kg−1 vs. light: 5.3 ± 0.3 W·kg−1, P = 0.006, effect size [ES] = 1.83; vs. middle: 5.3 ± 0.4 W·kg−1, P = 0.009, ES = 1.61). Relative O2peak during the MGT was lower in the heavy group than that in the other groups. The present study provides baseline physiological data that can be used in the prescription of individual training programs for wrestlers.

50 m Serbest Yüzme Performansının Alt Ekstremite Wingate Anaerobik Güç ve Kapasite Testi İle İlişkisi

Bu calismanin amaci, 50 m serbest yuzme performansinin alt ekstremite wingate anaerobik guc ve kapasite testi ile iliskisini incelemektir. Calismaya 11 erkek (yas: 13.45 ± 1.03 yil, boy: 166.18 ± 10.12 cm, vucut agirligi: 55.00 ± 11.13 kg, spor yasi: 6.2 ± 1.1 yil) performans yuzucusu gonullu olarak katilmistir. Tum deneklere ilk gun Wingate anaerobik guc ve kapasite testi, ikinci gun 50 m yuzme testi yapilmistir. Bu calismada 50 m serbest yuzme performansi standart bir atlama tasindan yapilmamistir, sporcu suyun icinden ve havuzun kenarindan yuzmeye baslamistir. Ayrica 10’ar metrelik gecis sureleri kayit edilmistir. Verilerin istatistiksel analizi Pearson Korelasyon analizi ile degerlendirilmis ve anlamlilik duzeyi olarak p 0.05). Yorgunluk indeksi ile relatif anaerobik kapasite, relatif minimum anaerobik guc ve minimum anaerobik guc arasinda istatistiksel olarak anlamli iliski bulunmustur (p 0.05). Yuzme performanslarindaki 10’ar metrelik gecis surelerinin Wingate anaerobik testi ile arasindaki iliskiye bakildiginda; yuzme maksimum hiz ile wingate anaerobik guc, yuzme ortalama hiz ile wingate anaerobik kapasite, yuzme minumum hiz ile wingate minumum guc degerleri arasinda hem relatif hem de absolut deger olarak istatistiksel olarak anlamli bir iliski bulunmustur (p 0.05). Bu sonucu; deneklerin spor yasi, profesyonellik duzeyi, suda ve karada yapilan aktivite arasindaki surtunme farki, ortam kosullari (nem, sicaklik vb.) gibi faktorler etkilemis olabilir

Effects of self-selected dehydration and meaningful rehydration on anaerobic power and heart rate recovery of elite wrestlers.

[Purpose] This study aimed to verify the effects of self-directed weight loss on lower- and upper-body power, fatigue index, and heart rate recovery immediately before a meaningful competition (12 hours of recovery). In addition, this study tested the hypothesis that weight loss provides advantages in strength and power, as the relative power of the wrestlers is higher than that of opponents in the same weight class who do not reduce weight. [Subjects and Methods] Eleven well-trained wrestlers volunteered for the study. At baseline, their mean ± SD age, body mass, and height were 20.45 ± 2.69 years, 74.36 ± 9.22 kg, and 177 ± 5.71 cm, respectively. Repeated-measures one-way analysis of variance was performed to analyze differences. [Results] Rapid weight loss achieved by restriction of energy and fluid intake resulted in exercise-impaired decreases in peak power and increased fatigue index. Moreover, weight loss by dehydration negatively affected cardiovascular stability. [Conclusion] Most of the negative effects of rapid weight loss disappear after a 12-hour recovery period, and relative peak power increases after weight loss.

Effects of a Short-Term In-Season Plyometric Training Program on Repeated-Sprint Ability, Leg Power and Jump Performance of Elite Handball Players

This study examined the effects of 8-weeks of in-season lower limb plyometric training on repeated-sprint ability (RSA), leg power and jumping performance in elite male handball players. Twenty-four participants (age 20 ± 0.3 years, body mass 89.1 ± 2.1 kg, height 1.88± 0.07 m, body fat 13.2 ± 1.3%) were randomly assigned to a control group (CG; n = 10, handball training only) or an experimental group (PG; n = 14, biweekly plyometric training, and handball training). The players were tested for RSA using a protocol of 6 × (2 × 15m) shuttle sprints, separated by 20 s of active recovery. Best time in a single trial (RSAbest), fastest total time (RSATT) and performance decrement (RSAdec) were determined. Leg power was determined by the peak power output (PP) during a 7-second all-out cycling test. Jump heights during the squat jump (SJ) and the countermovement jump (CMJ) were measured. Compared to the CG, PG significantly improved the RSAbest (p &lt; 0.01), RSATT (p &lt;0.01) and RSAdec (p &lt; 0.001), average PP (p &lt; 0.01) and all vertical jump performances (p &lt; 0.001 for SJ and p &lt;0.01 for CMJ). Biweekly plyometric training improved several aspects of RSA performance, leg power, and jumping performance during the season in elite male handball players. However, no interaction effect was found between the groups for the repeated sprint ability test (p = 0.062) or relative peak power (p=0.075). Coaches and strength and conditioning professionals should devote additional time for plyometric training in elite male handball players during the season to improve physical performance.

Effects of Whole-Body Vibration on Strength of Lower Extremities in Healthy Male Adults

In this paper, the authors investigated the effects of whole body vibration on strength of lower extremities. Thirty-three college healthy male students participated in this study. They were randomly divided into three trial groups. The trial consisted of 9 wks, each of which possesses 3 sessions.The test has been carried out pre- and post the trials. After analyzing the data,the findings showed that (1) the traditional resistance significantly increased strength of lower extremities on both absolute and relative peak torque and power, (2) the conventional training combined with vibration training can significantly increase the peak torque of extensors in lower extremities, and (3) the authors believed that the vibration training may be a better training method to improve the strength or power in lower extremities.However, the mechanism should be further investigated.

PPARA intron polymorphism associated with power performance in 30-s anaerobic Wingate Test.

To date, polymorphisms in several genes have been associated with a strength/power performance including alpha 3 actinin, ciliary neurotrophic factor, vitamin D receptor, or angiotensin I converting enzyme, underlining the importance of genetic component of the multifactorial strength/power-related phenotypes. The single nucleotide variation in peroxisome proliferator-activated receptor alpha gene (PPARA) intron 7 G/C (rs4253778; g.46630634G>C) has been repeatedly found to play a significant role in response to different types of physical activity. We investigated the effect of PPARA intron 7 G/C polymorphism specifically on anaerobic power output in a group of 77 elite male Czech ice hockey players (18–36 y). We determined the relative peak power per body weight (Pmax.kg−1) and relative peak power per fat free mass (W.kg−1 FFM) during the 30-second Wingate Test (WT30) on bicycle ergometer (Monark 894E Peak bike, MONARK, Sweden). All WT30s were performed during the hockey season. Overall genotype frequencies were 50.6% GG homozygotes, 40.3% CG heterozygotes, and 9.1% CC homozygotes. We found statistically significant differences in Pmax.kg−1 and marginally significant differences in Pmax.kg−1 FFM values in WT30 between carriers and non-carriers for C allele (14.6±0.2 vs. 13.9±0.3 W.kg−1 and 15.8±0.2 vs. 15.2±0.3 W.kg−1 FFM, P = 0.036 and 0.12, respectively). Furthermore, Pmax.kg−1 FFM strongly positively correlated with the body weight only in individuals with GG genotypes (R = 0.55; p<0.001). Our results indicate that PPARA 7C carriers exhibited higher speed strength measures in WT30. We hypothesize that C allele carriers within the cohort of trained individuals may possess a metabolic advantage towards anaerobic metabolism.

The ACTN3 R577X Polymorphism Is Associated With Muscle Power in Male Japanese Athletes

In this study, we investigated whether the ACTN3 R577X polymorphism is associated with muscular power in Japanese collegiate athletes by analyzing the mean and peak power results of a 30-second Wingate anaerobic test (WAnT) with respect to the ACTN3 R577X genotype in 253 Japanese athletes (144 men and 109 women). Each athlete performed a 30-second WAnT with a resistance equal to 7.5% of his or her body weight. Genotyping for the ACTN3 R577X (rs1815739) polymorphism was performed using the TaqMan approach. The ACTN3 R577X genotypes exhibited a Hardy-Weinberg equilibrium distribution in our population. The relative and absolute mean power results of the 30-second WAnT did not differ significantly among the genotypes. However, the relative peak power result of the WAnT was significantly higher in the R-allele-dominant model groups than in the XX group in male but not female athletes. These results suggest that the ACTN3 R allele is associated with the relative peak power during the WAnT in male Japanese collegiate athletes.

Understanding mismatches in body size, speed and power among adolescent rugby union players

With adolescent sport increasingly challenged by mismatches in size, new strategies are important to maximize participation. The objectives were to (1) improve the understanding of mismatches in physical size, speed and power in adolescent rugby union players, (2) explore associations between size and performance with demographic, playing-history, and injury profiles, and (3) explore the applicability of existing criteria for age/body mass-based dispensation (playing-down) strategies. Cross-sectional study. Four hundred and eighty-five male community rugby union players were recruited from three Australian states selected to represent community-based U12, U13, U14 and U15 players. Body mass, stature, speed (10, 30, and 40 m sprints) and lower-leg power (relative peak power and relative peak force) were measured. Independent student t-tests, linear regressions and Chi square analyses were undertaken. Mean values in age groups for size, speed and power masked considerable overlap in the ranges within specific age groups of adolescent rugby players. Only a small proportion of players (approximately 5%) shared the highest and lowest tertiles for speed, relative peak power and body mass. Physical size was not related to injury. The mean body mass of current community rugby union players was above the 75th percentile on normative growth-charts. The notion that bigger, faster, and more powerful characteristics occur simultaneously in adolescent rugby players was not supported in the present study. Current practices in body mass-based criteria for playing down an age group lack a sufficient evidence for decision-making. Dispensation solely based on body mass may not address mismatch in junior rugby union.

P307: Levodopa responsiveness of blink reflex recovery index – an objective method of differentiating Parkinson’s disease from Parkinson plus syndromes

P307: Levodopa responsiveness of blink reflex recovery index – an objective method of differentiating Parkinson’s disease from Parkinson plus syndromes

Peak-Power Instabilities of Laser Pulses Retroreflected by a Corner-Cube Retroreflector at Different Distances

In order to obtain the change in the return laser-pulse peak-power instability with the distance between two communication terminals in a free-space optical communication (FSO) asymmetric link, which uses a corner-cube retroreflector (CCR) and a high peak-power pulse laser, we present the peak power instability of laser pulses retroreflected by the CCR at different distances. The CCR bottom surface was a circle with a diameter of 1 in., and three mirrors of the CCR were coated with silver. The weather was cloudy with winds of Category 4. The distances from the transmitter to the CCR were 120, 1,550, 3,900, and 5,240 m. The laser emitted 100 laser pulses with a peak power of 5 MW at each distance. The results of the experiments show that the increase in both absolute and relative peakpower instabilities with the distance is approximately linear. The absolute peak-power instability is more than 58.7 mV and the relative peak-power instability is more than 11.8 % if the distance increases 1 km.

Energy and Macronutrient Intake of a Female Vegan Cyclist During an 8-Day Mountain Bike Stage Race

This report describes the dietary intake of a vegan mountain biker (height, 161 cm; weight, 49.6 kg; body mass index, 19.1 kg/m(2); relative peak power output, 4.6 W/kg) during the Transalp Challenge 2004 (altitude climbed, 22,500 m; total distance, 662 km), illustrating an aggressive dietary strategy that allowed the cyclist to be competitive. She finished the 8-stage event in 42 hours (mixed category, rank 16; 514 minutes behind the winners of this category), cycling with an average heart rate of 79.5% of laboratory-determined maximum, spending 892 minutes and 1627 minutes at intensities below and above 80%, respectively. During racing, the consumption of energy was 69.3 MJ (1.65 MJ/h), 65.76 MJ from carbohydrates (92 g/h), which was 35% of calories and 40% of carbohydrate total intake, and the fluid ingested was 3 L/day (570 mL/h), 55% of the total fluid consumed.

Anthropometric and Performance Characteristics of Elite Hurling Players

The purpose of the present study was to examine variations in the anthropometric and performance characteristics of elite hurling players in relation to playing position. Forty-one male, elite intercounty hurlers (25 ± 4 years), 4 goalkeepers, 8 full-backs, 8 halfback, 6 midfielders, 8 half-forwards and 7 full-forwards underwent measurements of standard anthropometric (stature, body mass, sum of five skinfolds and adipose tissue percentage estimates (%AT)) and performance characteristics (counter-movement jump (CMJ), CMJ peak power, CMJ relative peak power, 5-, 10-, 20-m sprint times and estimated V • O 2max ) during the later stages of the competitive season. A clear hierarchical anthropometric profile is evident with goalkeepers being the taller (184.3 ± 3.7 m), possessing the highest body mass (88.7 ± 5.7 kg) and adiposity (13.2 ± 3.1 %AT) than their outfield colleagues. Half-backs (47.4 ± 2.4 cm) and half-forwards (50.7 ± 5.9 cm) produced the highest CMJ scores; a similar profile was evident for sprint times. Midfielders (60.1 ± 1.4 mL.kg-1.min-1) exhibited a significantly (p<0.05) greater maximal oxygen uptake than all other playing positions. Differences in the anthropometric and performance characteristics of other playing positions whilst evident were non-significant. This study provides novel data, as it is the first report to present normative anthropometric and performance data for elite hurling players which to date has not been present in the literature. The enhanced maximal oxygen uptake in midfield players is likely due to different performance, technical and tactical demands associated with this position.

Influence of Rest Interval Duration on Muscular Power Production in the Lower-Body Power Profile

There is a paucity of evidence-based support for the allocation of rest interval duration between incremental loads in the assessment of the load-power profile. We examined the effect of rest interval duration on muscular power production in the load-power profile and sought to determine if greater rest is required with increasing load (i.e., variable rest interval). Ten physically trained men completed 4 experimental conditions in a crossover balanced design. Participants performed jump squats across incremental loads (0-60 kg) on 4 occasions, with an allocated recovery interval of 1, 2, 3, or 4 minutes. The mean log-transformed power output at each load was used for comparison between conditions (rest intervals). Unloaded jump squats (0 kg) maximized power output at each condition. The maximal mechanical power output was 66.6 ± 6.5 W·kg (1 minute), 66.2 ± 5.2 W·kg (2 minutes), 67.1 ± 5.9 W·kg (3 minutes), and 66.2 ± 6.5 W·kg (4 minutes). Trivial or unclear differences in power output were observed between rest intervals at each incremental load. As expected, power declined per 10 kg increment in load, the magnitude of decrease was 13.9-14.5% (confidence limits [CL]: ±1.3-2.0%) and 13.4-14.6% (CL: ±2.4-3.9%) for relative peak and mean power, respectively, yet differences in power output between conditions were likely insubstantial. The prescription of rest intervals between loads that are longer than 1 minute have a likely negligible effect on muscular power production in the jump squat incremental load-power profile. Practitioners should select either a 1- to 4-minute rest interval to best accommodate the logistical constraints of their monitoring sessions.

Appropriate Loads for Peak-Power During Resisted Sprinting on a Non-Motorized Treadmill

The purpose of this study was to determine the load which allows the highest peak power for resisted sprinting on a non-motorized treadmill and to determine if other variables are related to individual differences. Thirty college students were tested for vertical jump, vertical jump peak and mean power, 10 m sprint, 20 m sprint, leg press 1 RM, leg press 1 RM relative to body weight, leg press 1 RM relative to lean body mass, leg press 1 RM power, and leg press power at 80% of 1 RM. Participants performed eight resisted sprints on a non-motorized treadmill, with increasing relative loads expressed as percent of body weight. Sprint peak power was measured for each load. Pearson correlations were used to determine if relationships between the sprint peak power load and the other variables were significant. The sprint peak power load had a mode of 35% with 73% of all participants having a relative sprint peak power load between 25–35%. Significant correlations occurred between sprint peak power load and body weight, lean body mass, vertical jump peak and mean power, leg press 1 RM, leg press 1 RM relative to lean body mass, leg press 1 RM power, and leg press power at 80% of 1 RM (r = 0.44, 0.43, 0.39, 0.37, 0.47, 0.39, 0.46, and 0.47, respectively). Larger, stronger, more powerful athletes produced peak power at a higher relative load during resisted sprinting on a non-motorized treadmill.

Correlações entre parâmetros aeróbios e desempenho em esforços intermitentes de alta intensidade

O objetivo do presente estudo foi investigar as possíveis correlações entre parâmetros provenientes de um esforço intermitente de alta intensidade (RAST) e variáveis relacionadas ao metabolismo aeróbio (limiar anaeróbio; LAN, consumo máximo de oxigênio;VO2MAX e intensidade correspondente ao VO2MAX;iVO2MAX). Oito jogadores de futebol (16±1 anos) participaram do estudo. Os atletas foram submetidos a um teste progressivo para a determinação dos índices aeróbios e a seis esforços máximos de 35m separados por 10s de recuperação (RAST). As variáveis do RAST não foram correlacionadas ao VO2MAX e ao LAN. Entretanto, as potência média absoluta e relativa ao peso corporal, apresentaram correlações significativas com a iVO2MAX (r=0,79 e r= 0,85, respectivamente). O índice de fadiga e a potência pico relativa também foram significativamente correlacionados com a iVO2MAX (r=-0,57 e r=0,73, respectivamente). Pode-se concluir que em esforços como o RAST, com breves períodos de recuperação, a única variável aeróbia correlacionada ao desempenho foi a iVO2MAX.