Does improved decision-making ability reduce the physiological demands of game-based activities in field sport athletes?

This study investigated the effects of video-based perceptual training on pattern recognition and pattern prediction ability in elite field sport athletes and determined whether enhanced perceptual skills influenced the physiological demands of game-based activities. Sixteen elite women soccer players (mean +/- SD age, 18.3 +/- 2.8 years) were allocated to either a video-based perceptual training group (N = 8) or a control group (N = 8). The video-based perceptual training group watched video footage of international women's soccer matches. Twelve training sessions, each 15 minutes in duration, were conducted during a 4-week period. Players performed assessments of speed (5-, 10-, and 20-m sprint), repeated-sprint ability (6 x 20-m sprints, with active recovery on a 15-second cycle), estimated maximal aerobic power (V O2 max, multistage fitness test), and a game-specific video-based perceptual test of pattern recognition and pattern prediction before and after the 4 weeks of video-based perceptual training. The on-field assessments included time-motion analysis completed on all players during a standardized 45-minute small-sided training game, and assessments of passing, shooting, and dribbling decision-making ability. No significant changes were detected in speed, repeated-sprint ability, or estimated V O2 max during the training period. However, video-based perceptual training improved decision accuracy and reduced the number of recall errors, indicating improved game awareness and decision-making ability. Importantly, the improvements in pattern recognition and prediction ability transferred to on-field improvements in passing, shooting, and dribbling decision-making skills. No differences were detected between groups for the time spent standing, walking, jogging, striding, and sprinting during the small-sided training game. These findings demonstrate that video-based perceptual training can be used effectively to enhance the decision-making ability of field sport athletes; however, it has no effect on the physiological demands of game-based activities.     

Heart rate responses during small-sided games and short intermittent running training in elite soccer players: a comparative study

The purpose of this study was to compare heart rate (HR) responses within and between physical controlled (short-duration intermittent running) and physical integrated (sided games) training methods in elite soccer players. Ten adult male elite soccer players (age, 26 +/- 2.9 years; body mass, 78.3 +/- 4.4 kg; maximum HR [HRmax], 195.4 +/- 4.9 b x min(-1) and velocity at maximal aerobic speed (MAS), 17.1 +/- 0.8 km x h(-1)) performed different short-duration intermittent runs, e.g., 30-30 (30 seconds of exercise interspersed with 30 seconds of recovery) with active recovery, and 30-30, 15-15, 10-10, and 5-20 seconds with passive recovery, and different sided games (1 versus 1, 2 versus 2, 4 versus 4, 8 versus 8 with and without a goalkeeper, and 10 versus 10). In both training methods, HR was measured and expressed as a mean percentage of HR reserve (%HRres). The %HRres in the 30-30-second intermittent run at 100% MAS with active recovery (at 9 km.h with corresponding distance) was significantly higher than that with passive recovery (85.7% versus 77.2% HRres, respectively, p < 0.001) but also higher than the 1 versus 1 (p < 0.01), 4 versus 4 (p 相似文献   

Effects of two different half-squat training programs on fatigue during repeated cycling sprints in soccer players

This study compared the effects of two different half-squat training programs on the repeated-sprint ability of soccer players during the preseason. Twenty male professional soccer players were divided into 2 groups: One group (S-group) performed 4 sets of 5 repetitions with 90% of their 1-repetition maximum (1RM), and the other group (H-group) performed 4 sets of 12 repetitions with 70% of 1RM, 3 times per week for 6 weeks, in addition to their common preseason training program. Repeated-sprint ability was assessed before and after training by 10 × 6-second cycle ergometer sprints separated by 24 seconds of passive recovery. Maximal half-squat strength increased significantly in both groups (p < 0.01), but this increase was significantly greater in the S-group compared with the H-group (17.3 ± 1.9 vs. 11.0 ± 1.9%, p < 0.05). Lean leg volume (LLV) increased only in the H-group. Total work over the 10 sprints improved in both groups after training, but this increase was significantly greater in the second half (8.9 ± 2.6%) compared with the first half of the sprint test (3.2 ± 1.7%) only in the S-group. Mean power output (MPO) expressed per liter of LLV was better maintained during the last 6 sprints posttraining only in the S-group, whereas there was no change in MPO per LLV in the H-group over the 10 sprints. These results suggest that resistance training with high loads is superior to a moderate-load program, because it increases strength without a change in muscle mass and also results in a greater improvement in repeated sprint ability. Therefore, resistance training with high loads may be preferable when the aim is to improve maximal strength and fatigue during sprinting in professional soccer players.     

Morning versus evening power output and repeated-sprint ability

We investigated the effect of time-of-day on both maximal sprint power and repeated-sprint ability (RSA). Nine volunteers (22+/-4 yrs) performed a RSA test both in the morning (07:00 to 09:00 h) and evening (17:00 to 19:00 h) on different days in a random order. The RSA cycle test consisted of five, 6 sec maximal sprints interspersed by 24 sec of passive recovery. Both blood lactate concentration and heart rate were higher in the evening than morning RSA (lactate values post exercise: 13+/-3 versus 11+/-3 mmol/L(-1), p<0.05). The peak power developed during the first sprint was higher in the evening than morning (958+/-112 vs. 915+/-133 W, p<0.05), but this difference was not apparent in subsequent sprints, leading to a higher power decrement across the 5x6 sec test in the evening (11+/-2 vs. 7+/-3%, p<0.05). Both the total work during the RSA cycle test and the power developed during bouts 2 to 5 failed to be influenced by time-of-day. This suggests that the beneficial effect of time-of-day may be limited to a single expression of muscular power and fails to advantage performance during repeated sprints.     

Comparison of the physiological responses to different small-sided games in elite young soccer players

The purpose of this study was to compare the blood lactate (La-), heart rate (HR) and percentage of maximum HR (%HRmax) responses among the small-sided games (SSGs) in elite young soccer players. Sixteen players (average age 15.7 6 0.4 years; height 176.8 6 4.6 cm; body mass 65.5 6 5.6 kg; VO2max 53.1 6 5.9 ml · kg(-1) · min(-1); HRmax 195.9 6 7.4 b · min(-1)) volunteered to perform the YoYo intermittent recovery test and 6 bouts of soccer drills including 1-a-side, 2-a-side, 3-a-side, and 4-a-side games without a goalkeeper in random order at 2-day intervals. The differences in La-, HR and%HRmax either among the SSGs or among the bouts were identified using 4 x 6 (games x exercise bouts) 2-way analysis of variance with repeated measures. Significant differences were found on La-, HR, and %HRmax among the bouts (p ≤ 0.05). The 3-a-side and 4-a-side games were significantly higher than 1-a-side and 2-a-side games on HR and %HRmax (p ≤ 0.05), whereas the 1-a-side game significantly resulted in higher La- responses compared to other SSGs. This study demonstrated that physiological responses during the 1-a-side and 2-a-side games were different compared to 3-a-side and 4-a-side games. Therefore, it can be concluded that a decreased number of players results in increased intensity during SSGs including 6 bouts. These results suggest that coaches should pay attention on choosing the SSG type and the number of bouts to improve desired physical conditioning of elite young soccer players in soccer training.     

Sprint Conditioning of Junior Soccer Players: Effects of Training Intensity and Technique Supervision

The aims of the present study were to compare the effects of 1) training at 90 and 100% sprint velocity and 2) supervised versus unsupervised sprint training on soccer-specific physical performance in junior soccer players. Young, male soccer players (17 ±1 yr, 71 ±10 kg, 180 ±6 cm) were randomly assigned to four different treatment conditions over a 7-week intervention period. A control group (CON, n=9) completed regular soccer training according to their teams’ original training plans. Three training groups performed a weekly repeated-sprint training session in addition to their regular soccer training sessions performed at A) 100% intensity without supervision (100UNSUP, n=13), B) 90% of maximal sprint velocity with supervision (90SUP, n=10) or C) 90% of maximal sprint velocity without supervision (90UNSUP, n=13). Repetitions x distance for the sprint-training sessions were 15x20 m for 100UNSUP and 30x20 m for 90SUP and 90UNSUP. Single-sprint performance (best time from 15x20 m sprints), repeated-sprint performance (mean time over 15x20 m sprints), countermovement jump and Yo-Yo Intermittent Recovery Level 1 (Yo-Yo IR1) were assessed during pre-training and post-training tests. No significant differences in performance outcomes were observed across groups. 90SUP improved Yo-Yo IR1 by a moderate margin compared to controls, while all other effect magnitudes were trivial or small. In conclusion, neither weekly sprint training at 90 or 100% velocity, nor supervised sprint training enhanced soccer-specific physical performance in junior soccer players.     

Relation between maximal aerobic power and the ability to repeat sprints in young basketball players

The aim of this study was to examine the effects of maximal aerobic power (V(.-)O2max peak) level on the ability to repeat sprints (calculated as performance decrement and total sprinting time) in young basketball players. Subjects were 18 junior, well-trained basketball players (age, 16.8 +/- 1.2 years; height, 181.3 +/- 5.7 cm; body mass, 73 +/- 10 kg; V(.-)O2max peak, 59.6 +/- 6.9 ml x kg(-1) x min(-1)). Match analysis and time-motion analysis of competitive basketball games was used to devise a basketball-specific repeated-sprint ability protocol consisting of ten 15-m shuttle run sprints with 30 s of passive recovery. Pre, post, and post plus 3-minute blood lactate concentrations were 2.5 +/- 0.7, 13.6 +/- 3.1, and 14.2 +/- 3.5 mmol x L(-1), respectively. The mean fatigue index (FI) value was 3.4 +/- 2.3% (range, 1.1-9.1%). No significant correlations were found between V(.-)O2max peak and either FI or total sprint time. A negative correlation (r = -0.75, p = 0.01) was found between first-sprint time and FI. The results of this study showed that V(.-)O2max peak is not a predictor of repeated-sprint ability in young basketball players. The high blood lactate concentrations found at the end of the repeated-sprint ability protocol suggest its use for building lactate tolerance in conditioned basketball players.     

Changes evaluated in soccer-specific power endurance either with or without a 10-week,in-season,intermittent, high-intensity training protocol

The purpose of this study was to evaluate changes in soccer-specific power endurance of 34 female high school soccer players throughout a season either with or without an intermittent, high-intensity exercise protocol. Thirty-four female high school soccer players were tested prior to the 2000 fall season and again 10 weeks later. The tests included an abridged 45-minute shuttle test (LIST), hydrostatic weighing, vertical jump, 20-m running-start sprint, and 30-second Wingate test. The experimental group (EG; n = 17, age 16.5 +/- 0.9 years) completed a 10-week in-season plyometric, resistive training, and high-intensity anaerobic program. The control group (n = 17, age 16.3 +/- 1.4 years) completed only traditional aerobic soccer conditioning. Statistical significance was set at alpha < 0.05. The experimental group showed significant improvements in the LIST (EG = delta 394 seconds +/- 124 seconds), 20-m sprint (EG = Delta-0.10 seconds +/- 0.10 seconds), increase in fat-free mass (EG = delta 1.14 kg +/- 1.22 kg), and decreases in fat mass (EG = Delta-1.40 kg +/- 1.47 kg) comparing pre- to postseason. This study indicates that a strength and plyometric program improved power endurance and speed over aerobic training only. Soccer-specific power endurance training may improve match performance and decrease fatigue in young female soccer players.     

Activity profile of young soccer players during actual match play

This study investigated the activity profile of young soccer players (mean age 11.8 +/- 0.6 years; N = 12) with the aim of providing information for the development of training strategies. Data for movements of each player were obtained using 2 cameras that aimed at the subject throughout the match (Play Controller, Phromos, Italy). Encoders transmitted camera movements to a computer. The collected signals were then converted into distances, times, and speed attained at arbitrarily selected match categories. Players were monitored during official 11 vs. 11 matches (N = 12), with each match consisting of 2 halves, each lasting 30 minutes played on a regular soccer pitch. Mean total match distance amounted to 6,175 +/- 318 m. During the second half, players covered 5.5% less distance (p > 0.05). At speeds between 13.1 and 18.0 km.h(-1), players covered 12% less distance during the second half (p < 0.05). Players stood still 11% of the total time played (3,789 +/- 109 seconds). At speeds faster than 18 km.h(-1), players performed 33 +/- 4 bouts during match play, with a mean time length of 2.3 +/- 0.6 seconds per bout. Mean time interval between two successive maximal sprint bouts was 118.5 +/- 20.5 seconds. Players stood still longer during the course of the second half (229 +/- 76 seconds vs. 173 +/- 61 seconds, p < 0.05). Players tended to play in small areas of the football pitch and spent 9% of the total match time at high intensity. In order to promote a more active space coverage of the young player, at least for the age considered in the present study, the dimensions of the football pitch and the number of players should be reduced.     

Performance and fatigue during repeated sprints: what is the appropriate sprint dose?

When testing the ability of sportsmen to repeat maximal intensity efforts, or when designing specific training exercises to improve it, fatigue during repeated sprints is usually investigated through a number of sprints identical for all subjects, which induces a high intersubject variability in performance decrement in a typical heterogeneous group of athletes (e.g., team sport group, students, and research protocol volunteers). Our aim was to quantify the amplitude of the reduction in this variability when individualizing the sprint dose, that is, when requiring subjects to perform the number of sprints necessary to reach a target level of performance decrement. Fifteen healthy men performed 6-second sprints on a cycle ergometer with 24 seconds of rest until exhaustion or until 20 repetitions in case no failure occurred. Peak power output (PPO) was measured and a fatigue index (FI) computed. The variability in PPO decrement was compared between the 10th sprint and the sprint at which subject reached the target FI of 10%. Individual FI values after the 10th sprint were 14.6 ± 6.9 vs. 11.1 ± 1.2%, when individualizing the sprint dose, which corresponded to coefficients of interindividual variability of ～47.3 and ～10.8%, respectively. Individualizing the sprint dose substantially reduced intersubject variability in performance decrement, enabling a more standardized state of fatigue in repeated-sprints protocols designed to induce fatigue and test or train this specific repeated-sprint ability in a heterogeneous group of athletes. A direct feedback on the values of performance parameters is necessary between each sprint for the experimenter to set this individualized sprint dose.     

Small-Sided Games Versus Interval Training in Amateur Soccer Players: Effects on the Aerobic Capacity and the Ability to Perform Intermittent Exercises With Changes of Direction

ABSTRACT: Dellal, A, Varliette, C, Owen, A, Chirico, EN, and Pialoux, V. Small-sided games versus interval training in amateur soccer players: Effects on the aerobic capacity and the ability to perform intermittent exercises with changes of direction. J Strength Cond Res 26(10): 2712-2720, 2012-The purpose of this study was to compare the effects of small-sided games (SSGs) in soccer versus high-intensity intermittent training (HIT) on a continuous aerobic test (Vameval) and the performance in an intermittent test with changes of direction (CODs; 30-15 intermittent fitness test [30-15IFT]). Twenty-two amateur soccer players (mean age ± SD: 26.3 ± 4.7 years) were assigned to 3 different groups for 6 weeks: SSG group (n = 8), HIT group (n = 8), and control group (CG; n = 6). In addition to the usual technical and tactical sessions and competitive games, the SSG group performed 9 sessions of 2 versus 2 and 1 versus 1 SSGs, whereas the HIT group performed 9 sessions of intermittent runs in the form of 30 seconds of effort interspersed with 30 seconds of passive recovery (30s-30s), 15s-15s, and 10s-10s. The HIT and SSG groups showed performance improvements in the Vameval test (5.1 and 6.6%, respectively) and the 30-15IFT intermittent test with CODs (5.1 and 5.8%, respectively), whereas there was no change in the performance of the CG. Players from HIT and SSG groups showed similar increase in their performance in the 30-15IFT and the Vameval tests during the 6-week training period, especially with an increase significantly different to that in a traditional training as in the CG (p < 0.05). This investigation demonstrates that both SSG and HIT interventions are equally effective in developing the aerobic capacity and the ability to perform intermittent exercises with CODs in male amateur soccer players. Furthermore, these 2 methods of training applied during the 6 weeks induce similar effect on the recovery capacity and on the ability to repeat directional changes of 180°. Coaches will now be able to choose between these two methods according to the objective of the training and to optimize the training.     

Effects of speed, agility, quickness training method on power performance in elite soccer players

The purpose of this study was to evaluate the effects of the speed, agility, quickness (SAQ) training method on power performance in soccer players. Soccer players were assigned randomly to 2 groups: experimental group (EG; n = 50) and control group (n = 50). Power performance was assessed by a test of quickness--the 5-m sprint, a test of acceleration--the 10-m sprint, tests of maximal speed--the 20- and the 30-m sprint along with Bosco jump tests--squat jump, countermovement jump (CMJ), maximal CMJ, and continuous jumps performed with legs extended. The initial testing procedure took place at the beginning of the in-season period. The 8-week specific SAQ training program was implemented after which final testing took place. The results of the 2-way analysis of variance indicated that the EG improved significantly (p < 0.05) in 5-m (1.43 vs. 1.39 seconds) and in 10-m (2.15 vs. 2.07 seconds) sprints, and they also improved their jumping performance in countermovement (44.04 vs. 4.48 cm) and continuous jumps (41.08 vs. 41.39 cm) performed with legs extended (p < 0.05). The SAQ training program appears to be an effective way of improving some segments of power performance in young soccer players during the in-season period. Soccer coaches could use this information in the process of planning in-season training. Without proper planning of the SAQ training, soccer players will most likely be confronted with decrease in power performance during in-season period.     

Sprint patterns in rugby union players during competition

The purpose of this study was to characterize sprint patterns of rugby union players during competition. Velocity profiles (60 m) of 28 rugby players were initially established in testing from standing, walking, jogging, and striding starts. During competition, the individual sprinting patterns of 17 rugby players were determined from video by using the individual velocity profiles. Forwards commenced sprints from a standing start most frequently (41%), whereas backs sprinted from standing (29%), walking (29%), jogging (29%), and occasionally striding (13%) starts. Forwards and backs achieved speeds in excess of 90% maximal velocity (Vmax) on 5 +/- 4 and 9 +/- 4 occasions ( approximately 50% of the sprints performed), respectively, during competition. The higher frequency of sprinting for the backs compared with the forwards highlights the importance of speed training for this positional group. The similar relative distribution of velocities achieved during competition for forwards and backs suggests both positional groups should train acceleration and Vmax qualities. The backs should have a higher total volume of sprint training. Sprinting efforts should be performed from a variety of starting speeds to mimic the movement patterns of competition.     

Effect of recovery mode on repeated sprint ability in young basketball players

The aim of this study was to examine the effect of recovery mode on repeated sprint ability in young basketball players. Sixteen basketball players (age, 16.8 +/- 1.2 years; height, 181.3 +/- 5.7 cm; body mass, 73 +/- 10 kg; VO2max, 59.5 +/- 7.9 mL x kg(-1) x min(-1)) performed in random order over 2 separate occasions 2 repeated sprint ability protocols consisting of 10 x 30-m shuttle run sprints with 30 seconds of passive or active (running at 50% of maximal aerobic speed) recovery. Results showed that fatigue index (FI) during the active protocol was significantly greater than in the passive condition (5.05 +/- 2.4, and 3.39 +/- 2.3, respectively, p < 0.001). No significant association was found between VO2peak and FI and sprint total time (TT) in either repeated sprint protocols. Blood lactate concentration at 3 minutes post exercise was not significantly different between the 2 recovery conditions. The results of this study show that during repeated sprinting, passive recovery enabled better performance, reducing fatigue. Consequently, the use of passive recovery is advisable during competition in order to limit fatigue as a consequence of repeated high intensity exercise.     

Growth hormone responses to repeated maximal cycle ergometer exercise at different pedaling rates.

The present study examined the growth hormone (GH) response to repeated bouts of maximal sprint cycling and the effect of cycling at different pedaling rates on postexercise serum GH concentrations. Ten male subjects completed two 30-s sprints, separated by 1 h of passive recovery on two occasions, against an applied resistance equal to 7.5% (fast trial) and 10% (slow trial) of their body mass, respectively. Blood samples were obtained at rest, between the two sprints, and for 1 h after the second sprint. Peak and mean pedal revolutions were greater in the fast than the slow trial, but there were no differences in peak or mean power output. Blood lactate and blood pH responses did not differ between trials or sprints. The first sprint in each trial elicited a serum GH response (fast: 40.8 +/- 8.2 mU/l, slow: 20.8 +/- 6.1 mU/l), and serum GH was still elevated 60 min after the first sprint. The second sprint in each trial did not elicit a serum GH response (sprint 1 vs. sprint 2, P < 0.05). There was a trend for serum GH concentrations to be greater in the fast trial (mean GH area under the curve after sprint 1 vs. after sprint 2: 1,697 +/- 367 vs. 933 +/- 306 min x mU(-1) x l(-1); P = 0.05). Repeated sprint cycling results in an attenuation of the GH response.     

Activity profile of international-level soccer referees during competitive matches

The purpose of this study was to investigate the activity profile of soccer referees competing at international level. Thirteen international-level soccer referees (INRG, age 38 +/- 3 years, height 182.0 +/- 6.5 cm, and body mass 78.8 +/- 7.0 kg) were observed during official international matches using a match analysis system (Play Controller, Phromos, Italy) that enabled speeds and times collection for 11 arbitrarily chosen match categories. For comparison, 13 Italian elite-level soccer referees (NRG, age 37 +/- 3 years, height 182.5 +/- 3.5 cm, and body mass 77.1 +/- 6.5 kg) were examined during domestic official first division matches (Serie A). Results showed that NRG covered more distance during matches than the INRG (12,956 +/- 548 m and 11,218 +/- 1,056 m, respectively; p < 0.05). Running faster than 18 km.h(-1), NRG covered more distance than INRG (2,378 +/- 423 m and 1,642 +/- 689 m, respectively; p < 0.05). No between-halves differences in the distance covered at speed faster than 18 km.h(-1) were observed in each group. The main finding of this study is that international-level referees during international competitions are less active than national-level officials directing domestic matches. This unexpected result may suggest the need for specific training for the international referees, as recent reports have shown that better positioning is associated with longer space coverage during competitive matches. Across-halves, high-intensity, space-coverage conservation should be regarded as a peculiarity of the elite-level soccer referee.     

Sprinting patterns of National Rugby League competition

The purpose of this study was to investigate the sprinting demands of National Rugby League (NRL) competition and characterize the sprinting patterns of different rugby league playing positions. Thirty-seven elite rugby league players (mean ± SE age: 23.6 ± 0.5 years) underwent global positioning satellite analysis during 104 NRL appearances. The majority (67.5%) of sprint efforts were across distances of <20 m. The most common sprint distance for hit-up forwards was 6-10 m (46.3%). Outside backs had a greater proportion (33.7%) of sprint efforts over distances of ≥21 m. The proportion of sprint efforts over 40 m or greater for hit-up forwards, wide running forwards, adjustables, and outside backs was 5.0, 7.4, 5.0, and 9.7%, respectively. Of the sprints performed, approximately 48.0% involved contact, approximately 58.0% were preceded by forward locomotion (forward walking, jogging, or striding), whereas over 24.0% occurred from a standing start. Hit-up forwards more commonly sprinted from a standing start, or after lateral movement, whereas forward striding activities more commonly preceded sprint efforts for the adjustables and outside backs. The majority of sprint efforts were performed without the ball (78.7 vs. 21.3%). Most sprint efforts (67.5%) were followed by a long recovery (i.e., ≥5 minutes). Outside backs had the greatest proportion (76.1%) of long duration recovery periods and the smallest proportion (1.8%) of short duration recovery periods (i.e., <60 seconds) between sprints. The results of this study demonstrate differences among rugby league playing positions for the nature of sprint efforts and the typical distances covered during these efforts. Furthermore, the activities preceding and the recovery periods after sprint efforts were different among playing positions. These findings suggest that rugby league sprint training should be tailored to meet the individual demands of specific playing positions.     

Comparing the physical demands of friendly matches and small-sided games in semiprofessional soccer players

This study compared the physical demands of friendly matches (FMs) and small-sided games (SGs) in semiprofessional soccer players by means of global positioning system technology. Twenty-seven semiprofessional soccer players were monitored during 7 FMs and 9 sessions involving different SGs. Their physical profile was described on the basis of 20 variables related to distances and frequencies at different running speeds, the number of accelerations, and through global indicators of workload such as the work:rest ratio, player workload, and the exertion index. Results showed significant differences (p < 0.01) between SGs and FMs for the following variables: overall workload (SG > FM); the distribution of the distance covered in the speed zones 7.0-12.9 km·h(-1) (SG > FM) and >21 km·h(-1) (FM > SG); the distribution of time spent in certain speed zones (FM > SG: 0.0-6.9 and >21 km·h(-1); FM > SG: 7.0-12.9 km·h(-1)). More sprints per hour of play were performed during FMs, with greater mean durations and distances, greater maximum durations and distances, and a greater frequency per hour of play for sprints of 10-40 and >40 m (p < 0.01). The frequency of repeated high-intensity efforts was higher during FM (p < 0.01). The results show that coaches and strength and conditioning professionals should consider FMs during their training routine to foster specific adaptations in the domain of high-intensity effort.     

Purine loss after repeated sprint bouts in humans.

The influence of the number of sprint bouts on purine loss was examined in nine men (age 24.8 +/- 1.6 yr, weight 76 +/- 3.9 kg, peak O(2) consumption 3.87 +/- 0.16 l/min) who performed either one (B1), four (B4), or eight (B8) 10-s sprints on a cycle ergometer, 1 wk apart, in a randomized order. Forearm venous plasma inosine, hypoxanthine (Hx), and uric acid concentrations were measured at rest and during 120 min of recovery. Urinary inosine, Hx, and uric acid excretion were also measured before and 24 h after exercise. During the first 120 min of recovery, plasma inosine and Hx concentrations, and urinary Hx excretion rate, were progressively higher (P < 0.05) with an increasing number of sprint bouts. Plasma uric acid concentration was higher (P < 0.05) in B8 compared with B1 and B4 after 45, 60, and 120 min of recovery. Total urinary excretion of purines (inosine + Hx + uric acid) was higher (P < 0. 05) at 2 h of recovery after B8 (537 +/- 59 micromol) compared with the other trials (B1: 270 +/- 76; B4: 327 +/- 59 micromol). These results indicate that the loss of purine from the body was enhanced by increasing the number of intermittent 10-s sprint bouts.     

Heart Rate Monitoring in Soccer: Interest and Limits During Competitive Match Play and Training, Practical Application

ABSTRACT: Alexandre, D, Da Silva, C, Hill-Haas, S, Wong, DP, Natali, AJ, De Lima, JRP, Filho, MGB, Marins, JCB, Garcia, ES, and Chamari, K. Heart rate monitoring in soccer: Interest and limits during competitive match play and training-Practical application. J Strength Cond Res 26(10): 2890-2906, 2012-The identification of physiological loads imposed by soccer training or match play reveals essential information, which may help improve training and recovery strategies. Until today, the use of heart rate (HR) monitoring is not standardized in soccer. Thus, the aim of this review was to analyze, determine and compare the exercise intensity (EI) monitored by HR in professional, youth, and recreational soccer players during matches and training sessions using a meta-analysis. Heart rate is one of the most common physiological variables used to determine exercise internal training load. The mean EI recorded during competitive matches was described as 70-80% of V[Combining Dot Above]O2max or 80-90% of maximal heart rate (HRmax), independent of the playing level. With respect to HR training zones, approximately 65% of the total match duration is spent at intensity of 70-90% HRmax and rarely below 65% HRmax. However, although HRmax is mostly employed in the literature, monitoring EI should be expressed in relation to reserve heart rate, as it was described as a more reliable indicator of HR, allowing interindividual comparisons. The HR response according to the playing position indicates that midfielders are characterized by the highest EI, followed by forwards and fullbacks. Moreover, in the second half of the match, the EI is lower than that observed during the first half; this reduction could be correlated with the level of the player's physical conditioning. Consequently, coaches may favor the use of interval training or small-sided training games because these are shown to improve both aerobic capacity and the ability to repeat high-intensity actions. Small-sided games allow reaching similar HR responses to those found during interval training and match play but with greater heterogeneity values. Future investigations should include a larger sample of players with special reference to playing position and the expression of EI in percentage of the reserve heart rate, analyzing the possible intergender differences in HR response.