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Seihati A. Shiroma, Ursula F. Julio and Emerson Franchini

supplementary aerobic training program, judo athletes presented faster V ˙ O 2 recovery after a maximal graded exercise test (GET) and faster heart rate (HR) recovery after a high-intensity judo-specific test. 8 Thus, aerobic power development has been associated with faster creatine phosphate resynthesis

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Liam P. Kilduff, Huw Bevan, Nick Owen, Mike I.C. Kingsley, Paul Bunce, Mark Bennett and Dan Cunningham

Purpose:

The ability to develop high levels of muscle power is considered an essential component of success in many sporting activities; however, the optimal load for the development of peak power during training remains controversial. The aim of the present study was to determine the optimal load required to observe peak power output (PPO) during the hang power clean in professional rugby players.

Methods:

Twelve professional rugby players performed hang power cleans on a portable force platform at loads of 30%, 40%, 50%, 60%, 70%, 80%, and 90% of their predetermined 1-repetition maximum (1-RM) in a randomized and balanced order.

Results:

Relative load had a significant effect on power output, with peak values being obtained at 80% of the subjects’ 1-RM (4466 ± 477 W; P < .001). There was no significant difference, however, between the power outputs at 50%, 60%, 70%, or 90% 1-RM compared with 80% 1-RM. Peak force was produced at 90% 1-RM with relative load having a significant effect on this variable; however, relative load had no effect on peak rate of force development or velocity during the hang power clean.

Conclusions:

The authors conclude that relative load has a significant effect on PPO during the hang power clean: Although PPO was obtained at 80% 1-RM, there was no significant difference between the loads ranging from 40% to 90% 1-RM. Individual determination of the optimal load for PPO is necessary in order to enhance individual training effects.

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Dennis van Erck, Eric J. Wenker, Koen Levels, Carl Foster, Jos J. de Koning and Dionne A. Noordhof

the maximal oxygen uptake [ V ˙ O 2 max] and V ˙ O 2 at the lactate threshold), performance O 2 deficit, and gross mechanical efficiency (GE). GE, defined as the percentage of metabolic power input, that is, converted into mechanical power output (PO), is considered the most valid definition of

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Nicola Giovanelli, Filippo Vaccari, Mirco Floreani, Enrico Rejc, Jasmine Copetti, Marco Garra, Lea Biasutti and Stefano Lazzer

massagers. SMFR can promote short-term flexibility improvement, and it does not seem to have negative effects on performance. 2 , 3 , 9 – 11 In fact, no differences in maximal force and power were detected after an SMFR protocol. 2 , 12 Moreover, SMFR has been shown effective for reducing delayed

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Pedro Jiménez-Reyes, Fernando Pareja-Blanco, David Rodríguez-Rosell, Mario C. Marques and Juan José González-Badillo

Purpose:

To determine what variables determine the differences in performance on 2 tests of squat jump (SJ) performed under light load in highly trained athletes using maximal velocity (Vmax) or flight time (FT) as the discriminating factor of SJ performance.

Methods:

Thirty-two participants performed 2 maximal weighted SJs using a force platform synchronized with a linear transducer. Mean force (Fmean), mean and maximal power (Pmean, Pmax), peak force (PF), maximal rate of force development (RFDmax), and time required to attain PF (TPF) and RFDmax (TRFDmax) were analyzed. SJs were divided into 2 segments: from the initiation of force application to PF1 and from the moment after PF1 to Vmax.

Results:

Traditional significance statistics revealed significant differences in the same variables between best and worst SJs using both FT and Vmax. However, to use an approach based on the magnitude of the effect, the best SJ showed greater Pmax (83/17/0%), Pmean (85/15/0%), Fmean (71/29/0%), RFDmax1 (73/27/0%), and PF1 (53/47/0%) and lower TPF2 (0/61/39%) than the worst SJ when Vmax was used to discriminate SJ performance. However, using FT to differentiate SJ performance, no difference was observed between best and worst.

Conclusions:

Although jump height assessed through FT is a valid measure, these results suggest that Vmax is a more sensitive variable than FT to detect differences in loaded-SJ performance.

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Kristian M. O’Connor and Joseph Hamill

The ankle joint has typically been treated as a universal joint with moments calculated about orthogonal axes and the frontal plane moment generally used to represent the net muscle action about the subtalar joint. However, this joint acts about an oblique axis. The purpose of this study was to examine the differences between joint moments calculated about the orthogonal frontal plane axis and an estimated subtalar joint axis. Three-dimensional data were colected on 10 participants running at 3.6 m/s. Joint moments, power, and work were calculated about the orthogonal frontal plane axis of the foot and about an oblique axis representing the subtalar joint. Selected parameters were compared with a paired t-test (α = 0.05). The results indicated that the joint moments calculated about the two axes were characteristically different. A moment calculated about an orthogonal frontal plane axis of the foot resulted in a joint moment that was invertor in nature during the first half of stance, but evertor during the second half of stance. The subtalar joint axis moment, however, was invertor during most of the stance. These two patterns may result in qualitatively different interpretations of the muscular contributions at the ankle during the stance phase of running.

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Loren Z.F. Chiu and George J. Salem

Potentiation has been reported in power tasks immediately following a strength stimulus; however, only whole-body performance has been assessed. To determine the acute effects of weightlifting on vertical jump joint kinetics, performance was assessed before, during, and after snatch pull exercise in male athletes. Jumping was assessed using 3D motion analysis and inverse dynamics. Jump height was enhanced at the midpoint (5.77%; p = .001) and end (5.90%; p < .001) of the exercise session, indicating a greater powergenerating ability. At the midpoint, knee extensor net joint work was increased (p = .05) and associated with increased jump height (r = .57; p = .02). Following exercise, ankle plantar flexor net joint work was increased (p = .02) and associated with increased jump height (r = .67; p = .006). Snatch pull exercise elicited acute enhancements in vertical jump performance. At the midpoint of the exercise session, greater work at the knee joint contributed to enhanced performance. At the end of the exercise session, greater work at the ankle contributed to enhanced performance. Consequently, potentiation is not elicited uniformly across joints during multijoint exercise.

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Harsh H. Buddhadev and Philip E. Martin

studies have examined the effects of external power output and cadence on aerobic demand or energy expenditure ( Belli & Hintzy, 2002 ; Bigland-Ritchie & Woods, 1974 ; Chavarren & Calbet, 1999 ; Gaesser & Brooks, 1975 ; Marsh & Martin, 1993 ; Samozino, Horvais, & Hintzy, 2006 ). Influences of power

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Martin J. MacInnis, Aaron C.Q. Thomas and Stuart M. Phillips

than there is examining fixed-distance TTs. The mean power output (MPO) achieved during a 60-minute TT is a standard performance measure in cycling. In a study by Coyle et al, 3 60-minute MPO was the strongest predictor for the time required by well-trained cyclists to complete 40-km TTs in the field

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Samantha G. Fawkner and Neil Armstrong

The purpose of this study was to examine methods of assessing Critical Power (CP) with children. Eight boys and 9 girls (10.3 – 0.4 yrs) completed 3 cycle tests in one day, each at a different constant power output predicted to induce fatigue in 2 to 15 min. Time to exhaustion was recorded, and order of the tests was randomized, with 3 hours recovery between tests. The children repeated these tests and 2 additional tests with at least 24 hr recovery between each test. CP was determined using least squares linear regression analysis of the power — t−1 relationship, for the single day (CP1), the 5 tests from different days (CP2), and the repeated 3 tests from different days (CP3). The 95% limits of agreement (range of percentage differences) were −15.4 to 13.1% (CP1 v CP2), −16.8 to 13.5% (CP1 v CP3), and −8.4 to 6.7% (CP2 v CP3). CP is a robust measure even when only 3 tests are completed in a single day and may be used to provide a simple and useful parameter of exercise intensity for constant load exercise with children.