Suitability of soccer training drills for endurance training

Recent evidence suggests that certain soccer drills produce exercise intensities suitable for physical conditioning. However, it remains debatable whether soccer drills can provide a sufficiently unified exercise intensity among different players and on repetition of a drill, because movement patterns cannot be externally controlled during soccer drills. Good reliability and low variability of exercise intensity would enable all players to receive an appropriate training stimulus. The purpose of this study was to investigate intersubject variability and intrasubject reliability in exercise intensity during soccer drills. It was hypothesized that soccer drills that involve the highest exercise intensities would demonstrate the lowest intersubject variability and the highest intrasubject reliability. Heart rates of 23 professional soccer players were recorded during a range of soccer training drills. The drills consisted of 2 vs. 2 to 8 vs. 8 normal scoring games and 2 further possession games. Heart rate responses were examined for variability, reliability, and suitability for soccer endurance training. Coefficients of variation across players were less than 3% for all drills. Paired t-tests showed no significant differences in heart rate on repetition of the drills and 95% ratio limits of agreement were 1.8-3.8%. There were no significant correlations between exercise intensity and the statistical measures of variability and reliability. Several drills produced exercise intensities suitable for soccer endurance training with mean heart rate responses ranging from 87-91% HRmax. Soccer drills such as those used in the present study appear to be an adequate substitute for physical training without the ball and thus provide simultaneous skill and fitness training. The increase in training time spent developing technical ability and/or a reduction in total training time required may be useful for soccer teams.     

Measures of exercise intensity during soccer training drills with professional soccer players

Recent evidence supports the use of certain soccer drills for combined technical and physical training. Therefore, it is important to be able to accurately monitor training intensity during soccer drills intended for physical development to allow the optimization of training parameters. Twenty-eight professional soccer players were assessed for heart rate (HR) and rating of perceived exertion (RPE) responses to 5 commonly used soccer training drills (2v2 to 8v8 drills). The responses of both HR and RPE differed significantly (p < 0.05) between the drills, generally showing an elevated response to drills involving lower player numbers. However, the 2v2 drill showed a significantly (p < 0.05) lower HR response (mean +/- SD: 88.7 +/- 1.2% HRmax) than 3v3 (91.2 +/- 1.3% HRmax) and 4v4 drills (90.2 +/- 1.6% HRmax). There was no significant correlation between the HR and RPE responses to the various drills (r = 0.60, p = 0.200). This poor relationship is probably because during the 2v2 drill, RPE was higher than during any of the other 6 drills, whereas HR was only fourth highest of the 6 drills. This demonstrates that HR and RPE are only poorly related during the intense drills used in this study, and that HR underestimates the intensity of the 2v2 drill. Heart rate demonstrated lower intersubject variability (1.3-2.2%) than RPE (5.1-9.9%). However, unlike HR, Borg 15-point RPE appears to be a valid marker of exercise intensity over a wide range of soccer training drills by maintaining validity in all drills and demonstrating acceptable intersubject variability. A combination of both HR- and RPE-based training load calculations appears optimal for use in soccer training.     

Physical responses of different small-sided game formats in elite youth soccer players

A major use of small-sided games (SSGs) in soccer training is the concomitant development of game-specific aerobic fitness. We hypothesize that the SSG formats of 2 vs. 2, 3 vs. 3, and 4 vs. 4 players reveal game-like intensities and therefore are most adequate to increase game-specific aerobic fitness. Heart rate (HR), percentage of maximum heart rate (HRmax), blood lactate concentration (La), and time-motion characteristics of 17 elite male youth soccer players (aged 14.9 ± 0.7 years, V[Combining Dot Above]O2max 61.4 ± 4.5 ml·kg·min, HRmax 199.6 ± 7.3 b·min) were collected by global positioning systems while performing the SSG formats. Repeated-measures analysis of variance and effect sizes were calculated to demonstrate the differences between SSG formats. Highest physiological responses were obtained in 2 vs. 2 (HR: 186 ± 7 b·min, HRmax: 93.3 ± 4.2%, La: 5.5 ± 2.4 mmol·L) followed by 3 vs. 3 (HR: 184 ± 8 b·min, HRmax: 91.5 ± 3.3%, La: 4.3 ± 1.7 mmol·L) and 4 vs. 4 (HR: 179 ± 7 b·min, HRmax 89.7 ± 3.4%, La: 4.4 ± 1.9 mmol·L). Pronounced differences were found for most physiological parameters and for time spent in the speed zones "walking" (<5.3 km·h), "moderate-speed running" (10.3-13.9 km·h), and "maximum sprinting" (≥26.8 km·h). The findings suggest that all the formats reveal game-like intensities and are suitable for aerobic fitness improvements. However, we found pronounced demands on the anaerobic energy supply in 2 vs. 2, whereas 3 vs. 3 and 4 vs. 4 remain predominantly on an aerobic level and differ mainly in the HR response. We suggest using 3 vs. 3 for soccer-specific aerobic fitness training.     

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.     

Effects of playing surface (hard and clay courts) on heart rate and blood lactate during tennis matches played by high-level players

The aim of this study was to compare tennis matches played on clay (CL) and resin (R) courts. Six matches were played (3 on CL courts and 3 on R courts) by 6 high-level players. Heart rate (HR) was monitored continuously while running time (4.66 m), and blood lactate concentration ([La]) were measured every 4 games. Mean duration of points and effective playing time (EPT) were measured for each match. Mean HR (154 ± 12 vs. 141 ± 9 b · min(-1)) and [La] values (5.7 ± 1.8 vs. 3.6 ± 1.2 mmol · L(-1)) were significantly higher on CL (p < 0.05). The [La] increased significantly during the match on CL court. Mean duration of rallies (8.5 ± 0.2 vs. 5.9 ± 0.5 seconds) and EPT (26.2 ± 1.9 vs. 19.5 ± 2.0%) were significantly longer (p < 0.05) on CL. Running time values in speed tests were not significantly different between CL and R. Running time performance was not significantly decreased during the match, whatever the playing surface. This study shows that the court surface influences the characteristics of the match and the player's physiological responses. The court surface should be a key factor for consideration when coaches determine specific training programs for high-level tennis players.     

Heart rate responses and technical-tactical aspects of official 5-a-side youth soccer matches played on clay and artificial turf

Using a randomized crossover design, this study aimed to compare the heart rate (HR) responses and match analysis parameters (i.e., type of action; the number of players involved in an action; the number of passes performed in a collective action; precision of the shots; lost balls; ball interceptions; dribblings; and tackles) of official 5-a-side youth male soccer matches played over 2 pitch surface (i.e., clay vs. artificial turf) conditions. Twenty-two young male soccer players (age 8.3 ± 0.4 years) engaged in 2 consecutive 15-minute periods in each experimental condition. During the match, 53% of HR responses exceeded 85% of the individual HR(peak). No difference emerged between both pitch surfaces and match periods for HR and match analysis indicators. The two 15-minute periods resulted in being appropriate for 8-year-old players, in resembling the intensity of play and the intermittent nature of adult soccer. The similar HR responses and technical-tactical patterns observed on the 2 surfaces indicate that youth match play is not affected by differences in pitch surface. To support the development of individual and team skills of young soccer players, coaches are advised to prioritize game knowledge based on divergent thinking and experience, rather than traditional teaching based on instructions.     

A skill-based conditioning games approach to metabolic conditioning for elite rugby football players

The purpose of this study was to evaluate changes in endurance fitness of elite-level rugby union players (n = 35) undertaking skill-based conditioning games for a 9-week preseason training period. Metabolic conditioning was conducted exclusively in the form of skill-based conditioning games in conjunction with heart rate (HR) telemetry. Two markers of cardiorespiratory fitness were assessed at weekly intervals via the recording of HR responses to an intermittent multistage shuttle test. Significant differences post-training were observed for the percentage of maximal HR (% HRmax) reached during the final test stage and the percentage of HR recovery (% HR recovery) from the end of the final stage to the end of the final 1-minute rest period. Significant improvements were demonstrated for % HR recovery at week 7 (p < 0.05) and week 9 (p < 0.01), and % HRmax in the final test stage was significantly lower at weeks 4, 5, and 7 (p < 0.05) and week 9 (p < 0.01). Further improvements from mid-preseason to the end of the preseason training period were observed for % HR recovery scores in week 8 (p < 0.01) and week 9 (p = 0.012) and for % HRmax reached in the final test stage at week 9 (p < 0.05). These results indicate skill-based conditioning games were successful at improving markers of cardiorespiratory endurance for the duration of a 9-week training period in the elite-level professional rugby union players studied. The HR monitoring was demonstrated to be an effective and practical means of quantifying intensity in the conditioning games format and of tracking changes in cardiorespiratory fitness.     

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 the number of players and game type constraints on heart rate, rating of perceived exertion, and technical actions of small-sided soccer games

The purpose of this study was to identify the variation of heart rate (HR), rating of perceived exertion (RPE), and technical actions between 2 soccer small-sided games (SSGs; 3 × 3 and 4 × 4) in 3 game type constraints (when playing only offense [OFF], playing only defense [DEF], and both situations [GAME]). Sixteen high-level young male players were analyzed (age 15.75 ± 0.45 years; height 172.4 ± 4.83 cm; body mass 64.5 ± 6.44 kg; HRmax199.1 ± 9.08 b·min(-1); and 8.06 ± 1.98 years of soccer practice). All tasks were performed in 4 periods of 4 minutes interspersed with 2 minutes of active recovery. The HR was measured continuously and then analyzed by the time spent into 4 training zones according to individual %HRmax (zone 1 <75%; zone 2 75-84.9%; zone 3 85-89.9%; and zone 4 ≥90%). Results identified that players were most frequently in zones 2 and 3. The 3 × 3 SSGs elicited higher HR and RPE and the most intense situation was GAME. Despite the known higher frequencies from technical actions in SSGs with fewer players, player effectiveness in 3 × 3 and 4 × 4 was identical. The use of GAME, OFF, and DEF game type constraints should be carefully planned. Using the 3 × 3 format seems more adequate when aiming for aerobic performance optimal effects; however, DEF situations should only be used to promote aerobic recovery effects. The inclusion of an additional player in SSGs had different interactions in game type constraints, and only GAME presented adequate intensity.     

Physiological responses of skilled players during a competitive wheelchair tennis match

The purpose of this study was to determine heart rate (HR, b.min(-1)) response during competitive match play of 6 men who were skilled wheelchair (WC) tennis players. Each participant completed an arm crank ergometer test that measured HR via a telemetry device and O2 via open circuit spirometry from rest until fatigue (.V(O2)peak). Each athlete participated in 2 competitive singles matches during which HRs were recorded in 5-second intervals and O2 was estimated using the corresponding HR values recorded during the arm ergometer tests. Data analysis revealed an average playing intensity of 69.4 +/- 8.9% of HRpeak and 49.9 +/-14.5% of .V(O2)peak. In conclusion, it is recommended that skilled adult WC tennis players perform off-court aerobic conditioning as part of their training program, because the intensity of a competitive WC tennis match is sufficiently high enough to stress the cardiovascular system.     

Intensity of official Futsal matches

The purpose of this study was to assess the intensity of official Futsal matches, expressed in different ways. Fourteen male professional Futsal players from a First Division Brazilian team volunteered to participate in this study. Maximal oxygen uptake (VO(2)max) and the heart hate (HR) and oxygen uptake (VO(2)) correlation were determined for each player. The match intensity was estimated from the players' average HR measured during 13 National Futsal League matches. The HR measurements were obtained while the players were in the court but the values recorded while the players were sitting on the bench were not considered. In addition, these HR values were used to estimate the intensity of the effort expressed as a percentage of the maximal HR (% HRmax), percentage of VO(2)max (% VO(2)max), kilocalories per minute (kcal·min(-1)), and total caloric expenditure. The mean intensity of the matches was 86.4 ± 3.8% HRmax, 79.2 ± 9.0% VO(2)max, 18.0 ± 2.2 kcal·min(-1), and 313 ± 9.3 kcal. It was concluded that official Futsal matches have high intensity when expressed in the different ways used in this study. The information provided by this research can be used for planning the athletes' workouts, diets, and resting periods.     

Time-motion analysis of small-sided training games and competition in elite women soccer players

We investigated the movement patterns of small-sided training games and compared these movement patterns with domestic, national, and international standard competition in elite women soccer players. In addition, we investigated the repeated-sprint demands of women's soccer with respect to the duration of sprints, number of sprint repetitions, recovery duration, and recovery intensity. Thirteen elite women soccer players [age (mean +/- SD) 21 +/- 2 years] participated in this study. Time-motion analysis was completed during training (n = 39) consisting of small-sided (i.e., three versus three and five versus five) training games, domestic matches against male youth teams (n = 10), Australian national-league matches (n = 9), and international matches (n = 12). A repeated-sprint bout was defined as a minimum of three sprints, with recovery of less than 21 seconds between sprints. The overall exercise to rest ratios for small-sided training games (1:13) were similar to or greater than domestic competition against male youth teams (1:15) and national-league (1:16) and international (1:12) competitions. During the international matches analyzed, 4.8 +/- 2.8 repeated-sprint bouts occurred per player, per match. The number of sprints within the repeated-sprint bouts was 3.4 +/- 0.8. The sprint duration was 2.1 +/- 0.7 seconds, and the recovery time between sprints was 5.8 +/- 4.0 seconds. Most recovery between sprints was active in nature (92.6%). In contrast to international competition, repeated-sprint bouts were uncommon in small-sided training games, domestic competition against male youth teams, and national-league competition. These findings demonstrate that small-sided training games simulate the overall movement patterns of women's soccer competition but offer an insufficient training stimulus to simulate the high-intensity, repeated-sprint demands of international competition.     

Heart rate responses and technical comparison between small- vs. large-sided games in elite professional soccer

This study aims to examine the difference in heart rate (HR) responses and technical activities placed upon European elite players when exposed to 2-sided games differing in the number of players and playing area. Fifteen male soccer players from a Scottish Premier League team (26.3 ± 4.85 years, 182.4 ± 6.99 cm, 79.5 ± 8.05 kg, VO2max of 54.36 ± 5.45 ml·kg(-1)·min(-1)) performed both small (3 vs. 3 plus goalkeepers) and large (9 vs. 9 plus goalkeepers) sided games each lasting for 3 × 5 minutes interspersed with 4-minute passive recovery during the 2009-2010 season. The HR responses and players' technical actions were recorded throughout all sided games. Results show that small-sided games (SSG) induced significantly (p < 0.05, large effect) higher HR responses as compared to large-sided games. Furthermore, during SSGs, players spent significantly longer time in the >85% maximal HR zone (p < 0.05, large effect) as compared to large-sided games. Technical analysis revealed a large practical difference (effect size ranged from 1.5 to 21.2) between small- and large-sided games: less number of blocks, headers, interceptions, passes, and receives but more dribbles, shots, and tackles in SSG. Furthermore, SSG induced significantly lesser total ball contacts per game (p < 0.05, large effect) but significantly greater ball contacts per individual (p < 0.05, large effect) when compared to larger-sided games. The different technical requirements also enable coaches to carry out training games more suitable to specific playing positions such as SSG for midfielders (more dribbles, tackles, and ball contacts per player) strikers (more shots), and large-sided games for defender (more blocks, headers, and interceptions).     

Exercise intensity and technical demands of small-sided games in young Brazilian soccer players: effect of number of players, maturation, and reliability

The aims of this study were to examine in young soccer players (a) the effect of varying the number of players on exercise intensity (EI) and technical actions during small-sided games (SSGs), (b) the reliability of EI and technical actions, and (c) the influence of the players' maturation on EI and involvements with the ball (IWBs). Sixteen male soccer players (mean ± SD; age 13.5 ± 0.7 years, height 164 ± 7 cm, and weight 51.8 ± 8 kg) completed 2 bouts of 3 vs. 3 (SSG3), 4 vs. 4 (SSG4), and 5 vs. 5 (SSG5) training. Exercise intensity was measured using heart rate and expressed as a percentage of maximal heart rate (%MHR). Technical actions were quantified from video recordings. Maturation stage was determined with the Tanner scale. Exercise intensity in SSG3 (89.8 ± 2%MHR) was higher (p < 0.003) than that in SSG5 (86.9 ± 3%MHR). The EI in the first set (86.8 ± 4%MHR) was lower (p < 0.001) than that in the second (89.1 ± 3%MHR) and in the third set (89.4 ± 3%MRH). No effects of number of players were found in IWB, passes, target passes, tackles, and headers. Significantly more crosses, dribbling, and shots on goal were observed during SSG3 compared to during SSG4 or SSG5 (p < 0.05). The typical error for EI, expressed as coefficient of variation, ranged from 2.2 to 3.4%. The reliability for the most frequent technical actions ranged from 6.8 to 19.3%. The level of maturation was not correlated with either EI or IWB. These results extend previous findings with adult players suggesting that SSGs can provide an adequate training stimulus for young players and are feasible for groups with heterogeneous maturation levels.     

Sleep patterns and nocturnal cardiac autonomic activity in female athletes are affected by the timing of exercise and match location

The aim of the current study was to analyze the influence of the timing of training and matches, and match location, on sleep pattern and nocturnal cardiac autonomic activity in female soccer players. A total of 17 female soccer players (age: 21.6 ± 2.3 years; mean ± SD) wore wrist actigraph units and heart rate (HR) monitors during night-sleep throughout 18 night-training days (NTD), 18 resting days (RD), and 6 match-days (MD; 3 away-matches [AM] and 3 home-matches [HM]) of the competitive period. Training load was quantified by session rating of perceived exertion (sRPE), heart rate (HR), training impulse (TRIMP), and subjective well-being. In NTD, sleep onset time and total sleep time were significantly impaired compared to MD (+ 1:47 [0:48; 1:55] hours and ?1:35 [?1:42; ?0:57] hours, respectively; p< 0.001; mean difference ± 95% confidence interval [CI]) and RD (+ 1:31 [0:52; 1:49] hours and ?1:26 [?1:28; ?0:55] hours, respectively; p< 0.001). In AM, sleep onset time was delayed compared to HM (+ 0:36 [0:12; 0:44] hours; p< 0.001). Sleep latency was higher in NTD compared to RD (+ 4 [2; 5] min; p< 0.001), as well as after AM compared to HM (+ 5 [1; 7] min; p< 0.001). HR during sleep was significantly increased after NTD and MD compared to RD (+ 4 [1; 5] b.p.m and + 3 [1; 4] b.p.m, respectively; p< 0.001). Furthermore, HR variability decreased after NTD and MD compared to RD (e.g., lnRMSSD, ?0.09 [?0.18; ?0.08] ln[ms] and ?0.17 [?0.27; ?0.11] ln[ms], respectively; p< 0.001). Overall, the time of day for soccer practice (i.e., training at night) and match location (i.e., away matches) may cause disruption in sleep patterns and/or in autonomic cardiac activity in female soccer players. Additionally, playing official matches during the day and training at night may affect nocturnal cardiac autonomic activity by decreasing vagal-related modulation and increasing HR during sleep.     

The effect of players' standard and tactical strategy on game demands in men's basketball

The purpose of the present study was to examine the effects of competitive level and team tactic on game demands in men's basketball. Sixteen international-level male basketball players (INPs) and 22 national-level male basketball players (NLPs) were studied during 6 games. Time-motion analysis was performed to track game activities. Game physiological demands were assessed by monitoring heart rate (HR) and blood-lactate concentration. Results showed that INPs sprinted significantly more and performed more high-intensity shuffling than did NLPs (p < 0.05). Game-activity changes and frequency of high-intensity bouts were similar in man-to-man and zone-marking games (1,053 vs. 1,056 and 253 vs. 224, respectively, p > 0.05). Time spent in the maximal (>95% of HRmax) and high-intensity zone (85-95% of HRmax) was greater in the INPs than in the NLPs (17.8 vs. 15.2%, p < 0.01 and 59.1 vs. 54.4%, p < 0.05, respectively). No significant differences in mean HR were evident between man-to-man and zone-marking games (93.3 ± 2.1 vs. 92.8 ± 1.8% of HRmax, p > 0.05). Blood-lactate concentration was higher in the INPs than in the NLPs (6.60 ± 1.22 vs. 5.66 ± 1.19 mmol·L?1 at halftime and 5.65 ± 1.21 vs. 4.43 ± 1.43 mmol·L?1 at full time, p < 0.05). No mean or peak blood-lactate concentration differences resulted between man-to-man and zone-marking games (5.15 ± 1.32 vs. 5.83 ± 1.10 and 5.90 ± 1.25 vs. 6.30 ± 1.27 mmol·L?1, respectively, p > 0.05). These results suggest an effect of competitive level over game demands in men's basketball. No marking strategy effect was evident. Basketball coaches and fitness trainers should develop the ability to repeatedly perform high-intensity activity during the game. Repeated sprinting and high-intensity shuffling ability should be trained to successfully play man-to-man and zone defense, respectively.     

Evaluation of cardiovascular demands of game play and practice in women's ice hockey

Preparation for the physical demands of competition often involves game simulation during practice. This paradigm is thought to promote physiological adaptations that enhance maximal performance. However, a mismatch between practice intensity and actual competition intensity may not provide adequate training to achieve optimal game-play fitness. The purpose of this study was to evaluate the effectiveness of practice in meeting the cardiovascular demands of a women's ice hockey game. Heart rate (HR) data from 11 U.S. National Women's Ice Hockey team members were collected (5-second intervals) during a game and a typical practice session. Data was normalized to individual HRmax determined during Vo(2)max testing. Working time was defined as a game shift or practice-working interval. Mean working HR was greater during the game than the practice, 90 +/- 2% and 76 +/- 3% of HRmax, respectively (p < 0.05). Mean percent session time (game or practice) >90% HRmax was also longer during the game than the practice, 10.5 +/- 4.1% and 5.6 +/- 3.5% (p < 0.05), respectively. Mean session HR, percent time >80% HRmax, and mean resting HR were not different between game and practice (68 +/- 7% vs. 69 +/- 5%, 23.2 +/- 5.3% vs. 26.1 +/- 9.2%, and 59 +/- 8% vs. 56 +/- 5%, respectively). Elite women hockey players experience significantly greater cardiovascular load during game play than during practice. This mismatch in cardiovascular demand may prevent players from achieving "game shape," thus affecting competition play.     

Heart rate and blood lactate concentrations as predictors of physiological load on elite soccer players during various soccer training activities

The purpose of this investigation was to estimate the physiologic strain on players during various soccer training activities. Ten soccer players from the first division soccer league of Turkey were used as subjects. The heart rate responses were measured during 4 types of soccer training. First, the heart rates that corresponded to a blood lactate concentration of both 2 and 4 mM were measured, and then, during the 4 types of training, they were correlated with the proportion of time that the heart rate was below the 2-mM lactate line, between the 2- and 4-mM lactate lines, and above the 4-mM lactate line. Mean heart rates during friendly match, modified game, tactical training, and technical training activities were 157 +/- 19, 135 +/- 28, 126 +/- 21, and 118 +/- 21 b.min(-1), respectively. The differences between all of these soccer training activities were statistically significant (p < or = 0.01). The results demonstrate that (a) technical and tactical training consisted of very low exercise intensities (most of the heart rates were below the 4-mM lactate level) and (b) the percentages of time that the heart rate correlated to a point above the 4-mM lactate reference level during the friendly match and modified game were 49.6 +/- 27.1% and 23.9 +/- 24.5%, respectively. The practical implications of these findings are that, by using 2- to 4-mM reference lines, coaches can structure heart rate zones that can help determine the individualized exercise intensity for their players as well as estimate overall exercise intensity during soccer training.