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Ryu Nagahara, Jean-Benoit Morin and Masaaki Koido

Purpose:

To assess soccer-specific impairment of mechanical properties in accelerated sprinting and its relation with activity profiles during an actual match.

Methods:

Thirteen male field players completed 4 sprint measurements, wherein running speed was obtained using a laser distance-measurement system, before and after the 2 halves of 2 soccer matches. Macroscopic mechanical properties (theoretical maximal horizontal force [F0], maximal horizontal sprinting power [Pmax], and theoretical maximal sprinting velocity [V0]) during the 35-m sprint acceleration were calculated from speed–time data. Players’ activity profiles during the matches were collected using global positioning system units.

Results:

After the match, although F0 and Pmax did not significantly change, V0 was reduced (P = .038), and the magnitude of this reduction correlated with distance (positive) and number (negative) of high-speed running, number of running (negative), and other low-intensity activity distance (negative) during the match. Moreover, Pmax decreased immediately before the second half (P = .014).

Conclusions:

The results suggest that soccer-specific fatigue probably impairs players’ maximal velocity capabilities more than their maximal horizontal force-production abilities at initial acceleration. Furthermore, long-distance running, especially at high speed, during the match may induce relatively large impairment of maximal velocity capabilities. In addition, the capability of producing maximal horizontal power during sprinting is presumably impaired during halftime of a soccer match with passive recovery. These findings could be useful for players and coaches aiming to train effectively to maintain sprinting performance throughout a soccer match when planning a training program.

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Don W. Morgan

A growing body of literature has confirmed the health benefits of regular physical activity in school-aged youth. However, less systematic attention has been directed toward establishing activity profiles and evaluating the impact of community-based interventions designed to increase physical activity and reduce sedentary behavior in preschool children. In this paper, current findings are reviewed to determine whether preschoolers are achieving sufficient levels of structured and unstructured physical activity and to identify potential correlates of activity and sedentary behavior in the young child. In addition, promotion of physical activity among preschool-aged children in selected community settings is discussed and future research initiatives are highlighted. Given current trends in the overweight and obesity status of children aged two to five years, efforts aimed at increasing physical activity levels and documenting gains in health-related fitness and movement skillfulness in this pediatric population should be accelerated.

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In the article by Davis P, Wittekind A, and Beneke R, “Amateur Boxing: Activity Profile of Winners and Losers,” in Int J Sport Physiol Perform. 8(1), pp. 84–91, the digit zero was inadvertently deleted from some of the figures in the tables. Table 1, Total punches, Round 1 winners should be 20.7 not 2.7, and Round 3 winners should be 20.3 not 2.3. Table 2, Air punches, Round 1 winners should be 10.1 not 1.1, and Round 3 losers should be 10.6 not 1.6. Table 2, Punches/min, Round 2 should be 20.2 not 2.2, and Round 1 losers should be 20.2 not 2.2. Table 4, 2-punch-combinations, Round 2 winners should be 10.4 not 1.4, and Round 3 winners should be 10.2 not 1.2. We apologize for the error.

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Sheri J. Brock, Danielle Wadsworth, Nikki Hollett and Mary E. Rudisill

The School of Kinesiology at Auburn University is using Movband Technology to support online learning in their physical activity program. Active Auburn is a 2-hr credit course that encourages students (n = 2,000/year) to become physically active through online instruction and tracking physical activity using Movband technology. Movband technology allows for uploading and monitoring group physical activity data. The implementation of this technology has allowed the School of Kinesiology to: (a) promote physical activity on our campus, (b) serve a large number of students, (c) reduce demand on classroom/physical activity space, and (d) promote our research and outreach scholarship as well, by collecting physical activity profiles for students enrolled in the course. Students report they enjoy the course and that they appreciate the “freedom to exercise” when it best fits into their schedule. This course generates considerable revenue to support course instruction and much more for the School of Kinesiology.

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Monika Lohkamp, Simon Craven, Colin Walker-Johnson and Matt Greig

Context:

Postural stability diminishes with longer activity, which may increase the risk of injury. Tape can increase stability, but this effect diminishes after exercise.

Objective:

To investigate the influence of ankle taping on postural stability during soccer-specific activity.

Participants:

10 male, injury-free, semiprofessional soccer players.

Intervention:

A 45-min treadmill protocol replicating the activity profile of soccer match play—with and without ankle tape. Postural stability was assessed every 7.5 min, requiring response to sudden ankle plantar flexion and inversion during single-leg stance.

Main Outcome Measure:

Reaction time to perturbation and center- of-gravity (CoG) displacement.

Results:

Reaction time was significantly longer (P < .05) with longer exercise for both movements and conditions. No significant effect was evident in CoG displacement. For both outcome measures a nonsignificant benefit of taping was observed during the first 22.5 min of activity.

Conclusion:

Prolonged exposure to soccer-specific activity negates any beneficial effect of taping in improving postural stability.

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Paul R. Ford, Jeffrey Low, Allistair P. McRobert and A. Mark Williams

We examined the developmental activities that contribute to the development of superior anticipation skill among elite cricket batters. The batters viewed 36 video clips involving deliveries from bowlers that were occluded at ball release and were required to predict delivery type. Accuracy scores were used to create two subgroups: high-performing and low-performing anticipators. Questionnaires were used to record the participation history profiles of the groups. In the early stages of development, hours accumulated in cricket and other sports, as well as milestones achieved, did not differentiate groups. Significant between-group differences in activity profiles were found between 13 and 15 years of age, with high-performing anticipators accumulating more hours in structured cricket activity, and specifically in batting, compared with their low-performing counterparts.

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Tim J. Gabbett

Purpose:

A limitation of most rugby league time–motion studies is that researchers have examined the demands of single teams, with no investigations of all teams in an entire competition. This study investigated the activity profiles and technical and tactical performances of successful and less-successful teams throughout an entire rugby league competition.

Methods:

In total, 185 rugby league players representing 11 teams from a semiprofessional competition participated in this study. Global positioning system analysis was completed across the entire season. Video footage from individual matches was also coded via notational analysis for technical and tactical performance of teams.

Results:

Trivial to small differences were found among Top 4, Middle 4, and Bottom 4 teams for absolute and relative total distances covered and distances covered at low speeds. Small, nonsignificant differences (P = .054, ES = 0.31) were found between groups for the distance covered sprinting, with Top 4 teams covering greater sprinting distances than Bottom 4 teams. Top 4 teams made more meters in attack and conceded fewer meters in defense than Bottom 4 teams. Bottom 4 teams had a greater percentage of slow play-the-balls in defense than Top 4 teams (74.8% ± 7.3% vs 67.2% ± 8.3%). Middle 4 teams showed the greatest reduction in high-speed running from the first to the second half (–20.4%), while Bottom 4 teams completed 14.3% more high-speed running in the second half than in the first half.

Conclusion:

These findings demonstrate that a combination of activity profiles and technical and tactical performance are associated with playing success in semiprofessional rugby league players.

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Nicola Furlan, Mark Waldron, Mark Osborne and Adrian J. Gray

Purpose:

To assess the ecological validity of the Rugby Sevens Simulation Protocol (R7SP) and to evaluate its interday reliability.

Methods:

Ten male participants (20 ± 2 y, 74 ± 11 kg) completed 2 trials of the R7SP, separated by 7 d. The R7SP comprised typical running and collision activities, based on data recorded during international rugby sevens match play. Heart rate (HR) was monitored continuously during the R7SP, and the participants’ movements were recorded through a 20-Hz global positioning system unit. Blood lactate and rating of perceived exertion were collected before and immediately after the 1st and 2nd halves of the R7SP.

Results:

The average activity profile was 117 ± 5 m/min, of which 27 ± 2 m/min was covered at high speed, with a calculated energetic demand of 1037 ± 581 J/kg, of which ~40% was expended at a rate above 19 W/kg. Mean HR was 88% ± 4% of maximal HR. Participants spent ~45% ± 27% of time above 90% of maximal HR (t >90%HRmax). There were no significant differences between trials, except for lactate between the halves of the R7SP. The majority of the measured variables demonstrated a between-trials coefficient of variation (CV%) lower than 5%. Blood lactate measurements (14–20% CV) and t >90%HRmax (26% CV) were less reliable variables. In most cases, the calculated moderate worthwhile change was higher than the CV%.

Conclusions:

The R7SP replicates the activity profile and HR responses of rugby sevens match play. It is a reliable simulation protocol that can be used in a research environment to detect systematic worthwhile changes in selected performance variables.

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Rich D. Johnston, Tim J. Gabbett, David G. Jenkins and Michael J. Speranza

Purpose:

To assess the impact of different repeated-high-intensity-effort (RHIE) bouts on player activity profiles, skill involvements, and neuromuscular fatigue during small-sided games.

Participants:

22 semiprofessional rugby league players (age 24.0 ± 1.8 y, body mass 95.6 ± 7.4 kg).

Methods:

During 4 testing sessions, they performed RHIE bouts that each differed in the combination of contact and running efforts, followed by a 5-min off-side small-sided game before performing a second bout of RHIE activity and another 5-min small-sided game. Global positioning system microtechnology and video recordings provided information on activity profiles and skill involvements. A countermovement jump and a plyometric push-up assessed changes in lower- and upper-body neuromuscular function after each session.

Results:

After running-dominant RHIE bouts, players maintained running intensities during both games. In the contact-dominant RHIE bouts, reductions in moderate-speed activity were observed from game 1 to game 2 (ES = –0.71 to –1.06). There was also moderately lower disposal efficiency across both games after contact-dominant RHIE activity compared with running-dominant activity (ES = 0.62–1.02). Greater reductions in lower-body fatigue occurred as RHIE bouts became more running dominant (ES = –0.01 to –1.36), whereas upper-body fatigue increased as RHIE bouts became more contact dominant (ES = –0.07 to –1.55).

Conclusions:

Physical contact causes reductions in running intensity and the quality of skill involvements during game-based activities. In addition, the neuromuscular fatigue experienced by players is specific to the activities performed.

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Mitchell Mooney, Stuart Cormack, Brendan O’Brien and Aaron J Coutts

Purpose:

The purpose of this study was to determine if Yo-Yo Intermittent Recovery level 2 (Yo-Yo IR2) and the number of interchange rotations affected the match activity profile of elite Australian footballers.

Method:

Fifteen elite Australian footballers completed the Yo-Yo IR2 before the beginning of the season and played across 22 matches in which match activity profiles were measured via microtechnology devices containing a global positioning system (GPS) and accelerometer. An interchange rotation was counted when a player left the field and was replaced with another player. Yo-Yo IR2 results were further split into high and low groups.

Results:

Players match speed decreased from 1st to 4th quarter, while average-speed (m/min: P = .05) and low-speed activity (LSA, <15 km/h) per minute (LSA m/min; P = .06) significantly decreased in the 2nd half. Yo-Yo IR2 influenced the amount of m/min, high-speed running (HSR, >15 km/h) per minute (HSR m/min) and accelerometer load/min throughout the entire match. The number of interchanges significantly influenced the HSR m/min and m/min throughout the match except in the 2nd quarter. Furthermore, the low Yo-Yo IR2 group had significantly less LSA m/min in the 4th quarter than the high Yo-Yo IR2 group (92.2 vs 96.7 m/min, P = .06).

Conclusions:

Both the Yo-Yo IR2 and number of interchanges contribute to m/min and HSR m/min produced by elite Australian footballers, affecting their match activity. However, while it appears that improved Yo-Yo IR2 performance prevents reductions in LSA m/min during a match, higher-speed activities (HSR m/min) and overall physical activity (m/min and load/min) are still reduced in the 4th quarter compared with the 1st quarter.