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Sport-specific fitness testing differentiates professional from amateur soccer players where VO2max and VO2 kinetics do not
Abstract and Figures
The purpose of this study was to identify if sport-specific and cardiopulmonary exercise testing differentiated professional from amateur soccer players.
Thirty six men comprising 18 professional (mean±s: age 23.2±2.4 years) and 18 amateur (mean±SD: age 21.1±1.6 years) soccer players participated and performed four tests on separate occasions: 1) a graded exercise test to determine VO2max; 2) four exercise transients from walking to 80%Δ for the determination of VO2 kinetics; 3) the Yo-Yo Intermittent Recovery Test level 2 (Yo-Yo IR2) and 4) a repeated sprint test (RST).
The players did not differ in VO2max (professional 56.5±2.9 mL.kg-1.min-1; amateur 55.7±3.5 mL.kg-1.min-1: P=0.484) or VO2 kinetic fundamental measures (τ1 onset, professional 24.5±3.2 s; amateur 24.0±1.8 s: τ1 cessation, professional 28.7±2.8 s; amateur 29.3±3.5 s: P=0.923). However, the amateurs were outperformed in the Yo-Yo IR2 (Professional 966±153 m; Amateur 840±156 m) (P=0.034) and RST (best time, professional 6.46±0.27 s; amateur 6.84±0.24 s, P=0.012).
Performance indices derived from field-based sport-specific performance tests identified significant differences between professional and amateur players (P<0.05). However, neither tests of VO2 kinetics nor VO2max differentiated between groups, suggesting laboratory tests of cardiorespiratory parameters are probably less consequential to soccer than sport-specific field-based observations.
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... In addition, seasonal changes in the fitness of soccer players have also been examined by records of time to exhaustion (TE) and maximal aerobic speed (MAS) during maximal incremental tests performed in the laboratory or in field conditions. Although, the power of VO 2max to discriminate higher and lower-level players have not been unanimously reported (Marcos, Koulla & Anthos, 2018;Rampinini et al., 2009a;Slimani et al., 2019;Tonnessen et al., 2013;Wells et al., 2012;Ziogas et al., 2011), higher values of VO 2max have been positively associated with players in specific team position roles (midfielders) (Tonnessen et al., 2013). A better cardiovascular capacity, measures by means of VO 2max and MAS seems related to a lower perception of exercise intensity during trainings and games (Azcarate et al., 2020). ...
... Recent evidence suggests that the intermittent endurance capacity of players is improving over time (Elferink-Gemser et al., 2012). Moreover, the level of competitiveness of the player is related to the performance in: (i) soccer-specific endurance tests, such as the 30-15 and the Yo-Yo tests (Casado Yebras et al., 2014;Ingebrigtsen et al., 2012;Mohr, Krustrup & Bangsbo, 2003;Rampinini et al., 2009a;Wells et al., 2012), (ii) repeated sprint ability tests with (RSSA) (Rampinini et al., 2009b;Wells et al., 2012) or without (RSA) (Aziz et al., 2008) changes of direction and (iii) to the intermittent exercise performance during games (Mohr, Krustrup & Bangsbo, 2003). Additionally, a positive relationship was observed between team success in the league and the Yo-Yo intermittent endurance test level 2 (YYIE2) (Randers, Rostgaard & Krustrup, 2007) and the Yo-Yo intermittent recovery test level 2 (YYIR2) (Ingebrigtsen et al., 2012). ...
... Recent evidence suggests that the intermittent endurance capacity of players is improving over time (Elferink-Gemser et al., 2012). Moreover, the level of competitiveness of the player is related to the performance in: (i) soccer-specific endurance tests, such as the 30-15 and the Yo-Yo tests (Casado Yebras et al., 2014;Ingebrigtsen et al., 2012;Mohr, Krustrup & Bangsbo, 2003;Rampinini et al., 2009a;Wells et al., 2012), (ii) repeated sprint ability tests with (RSSA) (Rampinini et al., 2009b;Wells et al., 2012) or without (RSA) (Aziz et al., 2008) changes of direction and (iii) to the intermittent exercise performance during games (Mohr, Krustrup & Bangsbo, 2003). Additionally, a positive relationship was observed between team success in the league and the Yo-Yo intermittent endurance test level 2 (YYIE2) (Randers, Rostgaard & Krustrup, 2007) and the Yo-Yo intermittent recovery test level 2 (YYIR2) (Ingebrigtsen et al., 2012). ...
The physiological demands of soccer challenge the entire spectrum of the response capacity of the biological systems and fitness requirements of the players. In this review we examined variations and evolutionary trends in body composition, neuromuscular and endurance-related parameters, as well as in game-related physical parameters of professional players. Further, we explore aspects relevant for training monitoring and we reference how different training stimulus and situational variables (e.g., competition exposure) affect the physiological and performance parameters of players. Generally, improvements of small magnitude in non- (non-CMJ) and countermovement-based jumps (CMJBased) and in the sprint acceleration (ACCPhase) and maximal velocity phase (MVPhase) are observed from start of preparation phase (PPS) to beginning of competition phase (BCP). A greater magnitude of increases is observed in physiological and endurance performance measures within this period; moderate magnitude in sub-maximal intensity exercise (velocity at fixed blood lactate concentrations; V2–4mmol/l) and large magnitude in VO2max, maximal aerobic speed (MAS) and intense intermittent exercise performance (IE). In the middle of competition phase (MCP), small (CMJBased and ACCPhase), moderate (non-CMJ; MVPhase; VO2max; sub-maximal exercise) and large (MAS and IE) improvements were observed compared to PPS. In the end of competition period (ECP), CMJBased and MVPhase improve to a small extent with non-CMJ, and ACCPhase, VO2max, MAS, sub-maximal intensity exercise and IE revealing moderate increments compared to PPS. Although less investigated, there are generally observed alterations of trivial magnitude in neuromuscular and endurance-related parameters between in-season assessments; only substantial alterations are examined for IE and sub-maximal exercise performance (decrease and increase of small magnitude, respectively) from BCP to MCP and in VO2max and IE (decrements of small magnitude) from MCP to ECP. Match performance may vary during the season. Although, the variability between studies is clear for TD, VHSR and sprint, all the studies observed substantial increments in HSR between MCP and ECP. Finally, studies examining evolutionary trends by means of exercise and competition performance measures suggests of a heightened importance of neuromuscular factors. In conclusion, during the preseason players “recover” body composition profile and neuromuscular and endurance competitive capacity. Within in-season, and more robustly towards ECP, alterations in neuromuscular performance seem to be force-velocity dependent, and in some cases, physiological determinants and endurance performance may be compromised when considering other in-season moments. Importantly, there is a substantial variability in team responses that can be observed during in-season. Consequently, this informs on the need to both provide a regular training stimulus and adequate monitorization throughout the season.
... VO2Max needs of soccer players are explained in several theories and research results. International soccer player's average VO2Max 55 -68 ml/kg/min [20][21][22]. The minimum VO2Max requirement for soccer players aged 22-28 years is 54 -64 ml/kg/min for men and 50 -60 ml/kg/min for women [18,23]. ...
... Many theories and literature explain the VO2Max requirement of a soccer player. International soccer players average VO2Max 55 to 68 ml/kg/min [23], 48-62 ml/kg/min [22]. Professional 56.5 ml/kg/min; Amateur 55.7 ml/kg/min [24]. ...
... It is calculated in ml/kg/min using specific laboratory tests or field tests (Turnley, n.d;Hoff, 2007;Slimani et al., 2019). The maximum amount of oxygen that can be consumed during intense physical activity until fatigue occurs (Wells et al., 2012). ...
Students' health needs are one of the priorities in learning. Therefore, physical education, sports and health have a very significant role. Physical education, sports and health are not only a means of improving physical fitness, but also play a role in maintaining body health and understanding the local wisdom contained in traditional sports such as Massallo. Therefore, the aim of this research is how Massallo games can shape students' fitness and Vo2max. This research is a quantitative pre-experimental design research using a Pretest-Posttest one group design. With a total of 42 students participating, they used exercises with the Massallo game. All data obtained were searched for mean, min, max, and standard deviation values as well as differences in applying exercises and Massallo games using independent sample t-test and simple regression. There are differences in results in implementing training with Massallo games in increasing students' fitness and VO2Max. It was found that using the Massallo game training method had a difference of 11,421 in increasing students' fitness and VO2Max and had a significant influence of 0.610, which indicated that the Massallo game had a good role in students' fitness and VO2Max. Key Words: Fitness, Massallo Games, Physical Education, VO2Max
... This is thought to be one of the main causes of the decline in efficiency and, consequently, the emergence of indicators of muscular tiredness [10]. The VO2max of elite soccer players is typically between 50 and 75 mL/kg/min, but different values higher than 70 mL/kg/min have been identified [11]. ...
The aim of the study was to examine the association between cardiorespiratory and metabolic parameters and match running performance (MRP) in highly trained football players. The sample of participants consisted of 41 national-level football players (aged 23.20 ± 3.40 yrs, body height 182.00 ± 5.15 cm, and body mass 76.86 ± 6.06 kg) from the Serbian Super league. For the purposes of this research, the following measurements were applied. A maximal multistage progressive treadmill test, with a direct measurement of maximal oxygen consumption (VO2max) (using Fitmate MED, Cosmed, Rome, Italy) was conducted, alongside continuous heart rate monitoring. Capillary blood samples were taken from the hyperemic area using specific test strips, and, after sample collection, lactate concentration was immediately determined using a lactate analyzer. MRP variables were analyzed according to the BioIRC model of motion structure analysis, based on existing standards for profiling movement intensity. The results of multiple regression analysis indicated an association between cardiac parameters and total distance (R2 = 54.3%, p = 0.000), high-speed running (R2 = 46.4%, p = 0.000), and jogging (R2 = 33.6%, p = 0.004). Regression analysis revealed an association between cardiorespiratory parameters and total distance (R2 = 24.8%, p = 0.014), and high-speed running (R2 = 20%, p = 0.039). Meanwhile, no association was found between lactate concentration and running performance. The explanation for these regression analysis results is based on the observation that functional abilities represent significant potential for expressing movement performance, a crucial condition for success in football.
... Furthermore, in the present study, VȮ 2 peak was similar between the groups, and both groups had VȮ 2 peak values comparable to those of professional players at an international elite level. 13 VȮ 2 peak values have also previously been reported similar in football players across different levels, 28 indicating that VȮ 2 peak is not a limiting factor of physical football performance. ...
Purpose
In Football, the high‐intensity running bouts during matches are considered decisive. Interestingly, recent studies showed that peak fat oxidation rates (PFO) are higher in football players than other athletes. This study aimed to investigate whether PFO increases following a pre‐season. Secondarily, and due to COVID‐19, we investigated whether PFO is related to the physical performance in a subgroup of semi‐professional male football players.
Methods
Before and after 8 weeks of pre‐season training, 42 sub‐elite male football players (18 semi‐professionals and 24 non‐professionals) had a dual‐energy x‐ray absorptiometry scan and performed a graded exercise test on a treadmill for the determination of PFO, the exercise intensity eliciting PFO (Fatmax) and peak oxygen uptake (V̇O2peak). Additionally, the semi‐professional players performed a Yo‐Yo Intermittent Recovery Test level 2 (YYIR2) before and after pre‐season training to determine football‐specific running performance.
Results
PFO increased by 11 ± 10% (mean ± 95% CI), p = 0.031, and V̇O2peak increased by 5 ± 1%, p < 0.001, whereas Fatmax was unchanged (+12 ± 9%, p = 0.057), following pre‐season training. PFO increments were not associated with increments in V̇O2peak (Pearson's r² = 0.00, p = 0.948) or fat‐free mass (FFM) (r² = 0.00, p = 0.969). Concomitantly, YYIR2 performance increased in the semi‐professional players by 39 ± 17%, p < 0.001, which was associated with changes in V̇O2peak (r² = 0.35, p = 0.034) but not PFO (r² = 0.13, p = 0.244).
Conclusions
PFO, V̇O2peak, and FFM increased following pre‐season training in sub‐elite football players. However, in a subgroup of semi‐professional players, increments in PFO were not associated with improvements in YYIR2 performance nor with increments in V̇O2peak and FFM.
... From several theories, it is explained that the VO 2 max needs of football players are various. VO 2 max of international football players is 55-68 ml/kg/minute (Slimani et al., 2019), and 48-62 ml/kg/min (Wells et al., 2011). Professional 56.5 ml/kg/min; Amateur 55.7 ml/kg/min (Helgerud et al., 2001). ...
The purpose of this study was to determine the effect of small-sided games 5v5 on increasing aerobic endurance in football players. Materials and methods. This type of study is a quasi-experiment with a one-group pretest-posttest design. The population of this study was Gama Muda Football School (SSB) players in Pasaman Regency (Indonesia), totaling 60 persons. Sampling was performed using a targeted sampling technique, so the sample was determined to be a maximum of 20 individuals. The players’ endurance capacity was determined by measuring their VO2max capacity. The study used the Yo-Yo Intermittent Recovery Test (Yo-Yo IR Test) as an instrument to obtain research data. Data analysis in this study used the mean difference test (t-test) statistical method. Before testing our hypothesis, we first performed a normality test using the Lilliefors test. Results. After hypothesis testing, the results obtained show the value of t-count (10.15) > t-table (1.729), indicating that small-sided games 5v5 training effectively improves the aerobic endurance ability of young football players. Conclusions. The results of this study demonstrate that small-sided games 5v5 training can improve the aerobic endurance of young football players.
... Therefore, valid VO 2 max determination based on submaximal test can be a valuable alternative in clinical and sport applications. Lots of indirect methods have been developed, also taking into account the specificity of the sports discipline 3,10 or certain populations 2 . These indirect methods can be divided into two groups, i.e. those that require maximal effort (without monitoring VO 2 kinetics) and those that rely on submaximal trials or resting parameters. ...
The maximal oxygen uptake (VO2max) estimation has been a subject of research for many years. Cardiorespiratory measurements during incremental tests until exhaustion are considered the golden yard stick to assess VO2max. However, precise VO2max determination based on submaximal tests is attractive for athlete as well for clinical populations. Here, we propose and verify such a method based on experimental data. Using a recently developed model of heart rate (HR) and VO2 kinetics in graded exercise tests, we applied a protocol, which is terminated at 80% of the estimated maximal HR during ergometer cycling. In our approach, initially, formula for maximal HR is selected by retrospective study of a reference population (17 males, 23.5 ± 2.0 years, BMI: 23.9 ± 3.2 kg/m²). Next, the subjects for experimental group were invited (nine subjects of both sexes: 25.1 ± 2.1 years, BMI 23.2 ± 2.2 kg/m²). After calculation of maximal HR using cardiorespiratory recordings from the submaximal test, VO2max is predicted. Finally, we compared the prediction with the values from the maximal exercise test. The differences were quantified by relative errors, which vary from 1.2% up to 13.4%. Some future improvements for the procedure of VO2max prediction are discussed. The experimental protocol may be useful for application in rehabilitation assessment and in certain training monitoring settings, since physical exertion is not a prerequisite and the approach provides an acceptable VO2max estimation accuracy.
... Cardiopulmonary fitness is also often cited as a significant characteristic of success in soccer due to the large distances and continual dynamic movement patterns players are required to perform during a game [57]. Maximal or very high-intensity exercise in the heat causes a relevant impairment in oxygen delivery to the exercising muscles related to cardiac and muscle blood flow decreases [47,54]. ...
This study aimed to assess the capacity for repeated maximal effort (RME) of soccer players in the thermo-natural conditions (NC) and in simulated conditions for the 2022 FIFA World Cup in Qatar (QSC). Twenty-four semi-professional soccer players participated in the study. The exercise test consisted of ten 6-second maximal efforts on a cycloergometer. A 90-second passive rest interval was used. The test was performed in a Weiss Technik WK-26 climate test chamber in two different conditions: 1) thermo-neutral conditions (NC—20.5°C; 58.7% humidity); and 2) simulated conditions for the 2022 World Cup in Qatar (QSC—28.5 ± 1.92°C; 58.7 ± 8.64% humidity). Power-related, physiological, psychomotor, blood, and electrolyte variables were recorded. Results showed that (1) players achieved higher peak power (max 1607,46 ± 192,70 [W] - 3 rd rep), needed less time to peak power (min 0,95 ± 0,27 [s] - 3 rd rep), and had a higher fatigue slope (max 218,67 ± 59,64 [W/sek] - 7 th rep) in QSC than in NC (in each repetition of study protocol); (2) between the 1st repetition and subsequent repetitions a number of significants in among physiological, blood-related, and electrolyte variables were noted, but their direction was similar in both simulated conditions (e.g. V’O2/kg 37,59 ± 3,96 vs 37,95 ± 3,17 [ml/min/kg] - 3 rd rep, LAC 13,16 ± 2,61 vs 14,18 ± 3,13 [mg/dl] - 10 th rep or K 4,54 ± 0,29 vs 4,79 ± 0,36 [mmol/l] - 2 nd rep when compare QCS and NC respectively); (3) an 8°C of temperature difference between the climatic conditions did not significantly affect the soccer players’ physical and physiological responses in RME. The study results can be used in the design of training programs aimed to increase players’ physiological adaptations by simulating soccer-specific conditions of play in terms of anaerobic capacity, in particular, repetitive maximal efforts. These findings will be useful during the upcoming 2022 World Cup in Qatar and in locations where high ambient temperatures are customary.
... The question then arises whether the augmented V O 2 max translates into an enhanced ability to perform high-intensity exercise. A few studies have shown that V O 2 max differs between successful and unsuccessful teams within the same league [95,96], but no such pattern is apparent across top national leagues or between amateur and professional players [97,98]. Nor does V O 2 max correlate well with highintensity exercise during match-play [99] and appears to be a poor indicator of training status in professional players [100]. ...
Because physical demands are surging in football (soccer, USA), clubs are more and more seeking players who have a high capacity to perform repeated intense exercise. High-intensity interval training (HIIT), comprising exercise performed at intensities near or exceeding the capacity of aerobic energy systems, effectively enhances the physical conditioning of players. But given that HIIT imposes high loads, it increases the risk of overload-associated match performance decline and injury. This makes some coaches inclined to conduct HIIT in the weeks leading up to the season and during the season. Therefore, the challenge is how to optimize and dose HIIT during these phases, as they can be decisive. Studies have highlighted the utility of conducting periods of intensified training to overcome the risk of overload while at the same time enhancing performance. During intensified training periods of typically a few weeks, intensity is increased by enlarging the amount of HIIT, for example, aerobic high-intensity training or speed endurance training, while volume at low-to-moderate intensity is significantly reduced. The outcome depends on training composition and prescription—most notably, intensity and duration of bouts and recovery. When work intervals are prescribed for a few minutes at intensities > 90% heart rate max (i.e., aerobic high-intensity training), then beneficial adaptations pertaining to aerobic power and capacity are apparent. But when work intervals are conducted at much higher intensities, as all-out efforts or sprinting of typically 10- to 40-s duration with longer recovery periods (i.e., speed endurance training), beneficial adaptations pertaining to anaerobic energy systems, ion handling, and fatigue resilience are commonly observed. In this review, we discuss the utility of conducting intensified training periods to enhance performance in elite football players during the late preparation phase and competitive season.
The aim of this study was to investigate maximum aerobic power (VO2 max) and anaerobic threshold (AT) as determinants of training status among professional soccer players. Twelve professional 1st team British male soccer players (age: 26.2 ± 3.3 years, height: 1.77 ± 0.05 m, body mass: 79.3 ± 9.4 kg) agreed to participate in the study and provided informed consent. All subjects completed a combined test of anaerobic threshold (AT) and maximum aerobic power on two occasions: Test 1) following 5 weeks of low level activity at the end of the off-season and Test 2) immediately following conclusion of the competitive season. AT was assessed as both lactate threshold (LT) and ventilatory threshold (VT). There was no change in VO2 max between Test 1 and Test 2 (63.3 ± 5.8 ml·kg(-1)·min(-1) vs. 62.1 ± 4.9 ml·kg(-1)·min(-1) respectively), however, the duration of exercise tolerance (ET) at VO2 max was significantly extended from Test 1 to Test 2 (204 ± 54 vs. 228 ± 68 s respectively) (P<0.01). LT oxygen consumption was significantly improved in Test 2 versus Test 1 (P<0.01) VT was also improved (P<0.05). There was no significant difference in VO2 (ml·kg(-1)·min(-1)) corresponding to LT and VT. The results of this study show that VO2 max is a less sensitive indicator to changes in training status in professional soccer players than either LT or VT.
Numerous studies have suggested that dehydration is a causal factor to fatigue across a range of sports such as soccer; however, empirical evidence is equivocal on this point. It is also possible that exercise-induced moderate dehydration is purely an outcome of significant metabolic activity during a game. The diverse yet sustained physical activities in soccer undoubtedly threaten homeostasis, but research suggests that under most environmental conditions, match-play fluid loss is minimal (∼;1–2% loss of body mass), metabolite accumulation remains fairly constant, and core temperatures do not reach levels considered sufficiently critical to require the immediate cessation of exercise. A complex (central) metabolic control system which ensures that no one (peripheral) physiological system is maximally utilized may explain the diversity of research findings concerning the impact of individual factors such as dehydration on elite soccer performance. In consideration of the existing literature, we propose a new interpretative pacing model to explain the self-regulation of elite soccer performance and, in which, players behaviourally modulate efforts according to a subconscious strategy. This strategy is based on both pre-match (intrinsic and extrinsic factors) and dynamic considerations during the game (such as skin temperature, thirst, accumulation of metabolites in the muscles, plasma osmolality and substrate availability), which enables players to avoid total failure of any single peripheral physiological system either prematurely or at the conclusion of a match. In summary, we suggest that dehydration is only an outcome of complex physiological control (operating a pacing plan) and no single metabolic factor is causal of fatigue in elite soccer.
This study investigated the repeated-sprint ability (RSA) physiological responses to a standardized, high-intensity, intermittent running test (HIT), maximal oxygen uptake (VO(2) (max)) and oxygen uptake (VO(2)) kinetics in male soccer players (professional (N = 12) and amateur (N = 11)) of different playing standards. The relationships between each of these factors and RSA performance were determined. Mean RSA time (RSA(mean)) and RSA decrement were related to the physiological responses to HIT (blood lactate concentration ([La(-)]), r = 0.66 and 0.77; blood bicarbonate concentration ([HCO(3)-]), r = -0.71 and -0.75; and blood hydrogen ion concentration ([H(+)]), r = 0.61 and 0.73; all p < 0.05), VO(2) (max) (r = -0.45 and -0.65, p < 0.05), and time constant (tau) in VO(2) kinetics (r = 0.62 and 0.62, p < 0.05). VO(2) (max) was not different between playing standards (58.5 +/- 4.0 vs. 56.3 +/- 4.5 mL.kg(-1).min(-1); p = 0.227); however, the professional players demonstrated better RSA(mean) (7.17 +/- 0.09 vs. 7.41 +/- 0.19 s; p = 0.001), lower [La-] (5.7 +/- 1.5 vs. 8.2 +/- 2.2 mmol.L(-1); p = 0.004), lower [H+] (46.5 +/- 5.3 vs. 52.2 +/- 3.4 mmol.L(-1); p = 0.007), and higher [HCO3-] (20.1 +/- 2.1 vs. 17.7 +/- 1.7 mmol.L(-1); p = 0.006) after the HIT, and a shorter in VO2 kinetics (27.2 +/- 3.5 vs. 32.3 +/- 6.0 s; p = 0.019). These results show that RSA performance, the physiological response to the HIT, and differentiate between professional- and amateur-standard soccer players. Our results also show that RSA performance is related to VO(2) max, tau, and selected physiological responses to a standardized, high-intensity, intermittent exercise.
The physiological determinants of performance in two Yo-Yo intermittent recovery tests (Yo-YoIR1 and Yo-YoIR2) were examined in 25 professional (n = 13) and amateur (n = 12) soccer players. The aims of the study were (1) to examine the differences in physiological responses to Yo-YoIR1 and Yo-YoIR2, (2) to determine the relationship between the aerobic and physiological responses to standardized high-intensity intermittent exercise (HIT) and Yo-Yo performance, and (3) to investigate the differences between professional and amateur players in performance and responses to these tests. All players performed six tests: two versions of the Yo-Yo tests, a test for the determination of maximum oxygen uptake (V(O)(2)(max)), a double test to determine V(O)(2) kinetics and a HIT evaluation during which several physiological responses were measured. The anaerobic contribution was greatest during Yo-YoIR2. V(O)(2)(max) was strongly correlated with Yo-YoIR1 (r = 0.74) but only moderately related to Yo-YoIR2 (r = 0.47). The time constant (tau) of V(O)(2) kinetics was largely related to both Yo-Yo tests (Yo-YoIR1: r = 0.60 and Yo-YoIR2: r = 0.65). The relationships between physiological variables measured during HIT (blood La(-), H(+), HCO(3) (-) and the rate of La(-) accumulation) and Yo-Yo performance (in both versions) were very large (r > 0.70). The physiological responses to HIT and the tau of the V(O)(2) kinetics were significantly different between professional and amateur soccer players, whilst V(O)(2)(max) was not significantly different between the two groups. In conclusion, V(O)(2)(max) is more important for Yo-YoIR1 performance, whilst tau of the V(O)(2) kinetics and the ability to maintain acid-base balance are important physiological factors for both Yo-Yo tests.
Numerous studies have suggested that dehydration is a causal factor to fatigue across a range of sports such as soccer; however, empirical evidence is equivocal on this point. It is also possible that exercise-induced moderate dehydration is purely an outcome of significant metabolic activity during a game. The diverse yet sustained physical activities in soccer undoubtedly threaten homeostasis, but research suggests that under most environmental conditions, match-play fluid loss is minimal ( approximately 1-2% loss of body mass), metabolite accumulation remains fairly constant, and core temperatures do not reach levels considered sufficiently critical to require the immediate cessation of exercise. A complex (central) metabolic control system which ensures that no one (peripheral) physiological system is maximally utilized may explain the diversity of research findings concerning the impact of individual factors such as dehydration on elite soccer performance. In consideration of the existing literature, we propose a new interpretative pacing model to explain the self-regulation of elite soccer performance and, in which, players behaviourally modulate efforts according to a subconscious strategy. This strategy is based on both pre-match (intrinsic and extrinsic factors) and dynamic considerations during the game (such as skin temperature, thirst, accumulation of metabolites in the muscles, plasma osmolality and substrate availability), which enables players to avoid total failure of any single peripheral physiological system either prematurely or at the conclusion of a match. In summary, we suggest that dehydration is only an outcome of complex physiological control (operating a pacing plan) and no single metabolic factor is causal of fatigue in elite soccer.
We assessed the linearity of oxygen uptake (VO2) kinetics for several work intensities in four trained cyclists. VO2 was measured breath by breath during transitions from 33 W (baseline) to work rates requiring 38, 54, 85, and 100% of maximal aerobic capacity (VO2max). Each subject repeated each work rate four times over 8 test days. In every case, three phases (phases 1, 2, and 3) of the VO2 response could be identified. VO2 during phase 2 was fit by one of two models: model 1, a double exponential where both terms begin together close to the start of phase 2, and model 2, a double exponential where each of the exponential terms begins independently with separate time delays. VO2 rose linearly for the two lower work rates (slope 11 ml.min-1 W-1) but increased to a greater asymptote for the two heavier work rates. In all four subjects, for the two lighter work rates the double-exponential regression reduced to a single value for the time constant (average across subjects 16.1 +/- 7.7 s), indicating a truly monoexponential response. In addition, one of the responses to the heaviest work rate was monoexponential. For the remaining seven biexponential responses to the two heaviest work rates, model 2 produced a significantly better fit to the responses (P less than 0.05), with a mean time delay for the slow component of 105 +/- 46 s.(ABSTRACT TRUNCATED AT 250 WORDS)
This study was designed to ascertain whether 7- and 13-wk interval training programs with training frequencies of 2 days/wk would produce improvement in maximal aerobic power (VO2max) comparable to that obtained from 7- and 13-wk programs of the same intensity consisting of 4 training days/wk. Sixty-nine young healthy college males were used as subjects. After training, there was a significant increase in VO2max (bicycle ergometer, open-circuit spirometry) that was independent of both training frequency and duration. However, there was a trend for greater gains after 13 wk. Maximal heart rate (direct lead ECG) was significantly decreased following training, being independent of both training frequency and duration. Submaximal VO2 did not change with training but submaximal heart rate decreased significantly with greater decreases the more frequent and longer the training. Within the limitations of this study, these results indicate that: 1) maximal stroke volume and/or maximal avO2 difference, principle determinants of VO2max, are not dependent on training frequency nor training duration, and 2) one benefit of more frequent and longer duration interval training is less circulatory stress as evidenced by decreased heart rate, during submaximal exercise.
1. At work rates which do not result in a sustained increase in blood lactate ([L-]), oxygen uptake (VO2) approaches the steady state with first-order kinetics. However, when [L-] is increased, at least two kinetic components are required to characterize the VO2 response dynamics. The purpose of the present investigation was to determine whether these more-complex kinetics are best represented as: (a) two components which operate throughout the exercise or (b) a delayed slow component which is consequent to the lactic acidaemia and which does not influence the early development of the O2 deficit. 2. Six healthy subjects underwent an incremental ramp test on a cycle ergometer, to the limit of tolerance, for determination of the maximum VO2 (micro VO2) and and estimation [symbol: see text] of the threshold for lactic acidaemia (theta L) non-invasively. Subjects then performed, on different days, two to four repetitions of square-wave exercise from a baseline of unloaded pedalling ('O' Watts (W)) to work rates (WR) less than theta L (90% theta L) and greater than theta L (half-way between theta L and micro VO2). Ventilatory and pulmonary gas exchange variables were determined breath-by-breath. For each subject, the VO2 transitions were averaged prior to fitting a least-squares algorithm to the on- and off-transient responses. 3. The less than theta L test resulted in a mono-exponential VO2 response, with a time constant of 31.3 and 31.5 s for the on- and off-transients, respectively. 4. The VO2 responses to the greater than theta L test were fitted to three competing models: (a) a single exponential for the entire period; (b) a double exponential for the entire period; and (c) an initial single exponential with a subsequent phase of delayed onset. Model (c) yielded a significantly lower residual mean-squares error than methods (a) and (b), with a time constant for the initial component of 40.2 s for the on-transient and 32.9 s for the off-transient and a subsequent phase of VO2 increase for the on-transient which averaged 230 ml min-1. The delta VO2/delta WR for the early kinetics of the greater than theta L test were not different from the less than theta L test (9.6 and 9.5 ml min-1 W-1, respectively). 5. These data suggest that the slow phase of the greater than theta L VO2 kinetics is a delayed-onset process. This being the case, the O2 deficit during heavy exercise, as conventionally estimated, would be overestimated.