Physiological and anthropometric characteristics of junior rugby league players over a competitive season

This study investigated the physiological and anthropometric characteristics of junior rugby league players over a competitive season. Forty-five rugby league players were allocated into training (n = 36) and nonexercise control (n = 9) groups. The training group participated in 2 field-training sessions each week with training loads, match loads, and injury rates recorded. Subjects performed measurements of standard anthropometry (height, body mass, and sum of 7 skinfolds), muscular power (vertical jump), speed (10-, 20-, and 40-m sprint), agility ('L run'), and estimated maximal aerobic power (multi-stage fitness test) in December (off-season), March (preseason), May (midseason), and August (end-season). Training loads progressively increased in the general preparatory phase of the season (preseason period), and declined slightly during the competitive phase of the season. Match intensity and match loads decreased throughout the season. Increases in estimated maximal aerobic power and muscular power and reductions in skinfold thickness occurred during the general preparatory phase of the season, and were maintained throughout the competitive phase of the season. These findings suggest that high training loads in the general preparatory phase of the season and low match loads in the competitive phase of the season allow junior rugby league players to maintain a high level of fitness throughout an entire competitive season.     

Strength training affects tendon cross-sectional area and freely chosen cadence differently in noncyclists and well-trained cyclists

The effects of strength training on freely chosen cadence and physiological responses in cyclists and recreationally active individuals were investigated. Well-trained cyclists were assigned to either usual endurance training combined with strength training (C-ES; n = 11) or usual endurance training only (C-E; n = 9). Recreationally active individuals (R-S; n = 7) performed the same strength training as C-ES did (4 lower body exercises, 3 × 4-10 repetition maximum [RM], twice a week for 12 weeks). The R-S and C-ES increased 1RM to a similar extent after 4 and 12 weeks (p < 0.01), whereas 1RM remained unchanged in C-E. Only R-S increased patellar tendon cross-sectional area (CSA; 7 ± 1%, p < 0.001). After 4 weeks, R-S reduced freely chosen cadence, oxygen consumption, heart rate, rating of perceived exertion, and blood lactate concentration during cycling at 125 W. These responses remained reduced throughout the intervention period (p < 0.05). No significant changes were observed in these physiological variables in C-ES and C-E. In conclusion, freely chosen cadence during submaximal cycling was reduced in recreationally active individuals after a period of strength training but was not reduced in well-trained cyclists. The reduced freely chosen cadence may be associated with the observed increase in patellar tendon CSA through a morphological-sensory-motor interaction. A practical application is that heavy strength training can reduce freely chosen cadence during submaximal cycling and thereby improve cycling economy in recreationally active individuals, whereas other mechanisms should account for improved performance after strength training in well-trained cyclists.     

Accelerometry-based variables in professional soccer players: comparisons between periods of the season and playing positions

The aim of this study was to provide reference data of variation in external training loads for weekly periods within the annual season. Specifically, we aimed to compare the weekly acute load, monotony, and training strain of accelerometry-based measures across a professional soccer season (pre-season, first and second halves of the season) according to players’ positions. Nineteen professional players were monitored daily for 45 weeks using an 18-Hz global positioning system to obtain measures of high metabolic load distance (HMLD), impacts, and high intensity accelerations and decelerations. Workload indices of acute load, training monotony, and training strain were calculated weekly for each of the measures. The HMLD had greater training strain values in the pre-season than in the first (p ≤ 0.001; d = 0.793) and second halves of the season (p ≤ 0.001; d = 0.858). Comparisons between playing positions showed that midfielders had the highest weekly acute load of HMLD (6901 arbitrary units [AU]), while central defenders had the lowest (4986 AU). The pre-season period was associated with the highest acute and strain load of HMLD and number of impacts, with a progressive decrease seen during the season. In conclusion, coaches should consider paying greater attention to variations in HMLD and impacts between periods of the season and between players to individualize training accordingly.     

Training load,recovery and game performance in semiprofessional male basketball: influence of individual characteristics and contextual factors

This study examined the effects of individual characteristics and contextual factors on training load, pre-game recovery and game performance in adult male semi-professional basketball. Fourteen players were monitored, across a whole competitive season, with the session-RPE method to calculate weekly training load, and the Total Quality Recovery Scale to obtain pre-game recovery scores. Additionally, game-related statistics were gathered during official games to calculate the Performance Index Rating (PIR). Individual characteristics and contextual factors were grouped using k-means cluster analyses. Separate mixed linear models for repeated measures were performed to evaluate the single and combined (interaction) effects of individual characteristics (playing experience; playing position; playing time) and contextual factors (season phase; recovery cycle; previous game outcome; previous and upcoming opponent level) on weekly training load, pre-game recovery and PIR. Weekly load was higher in guards and medium minute-per-game (MPG) players, and lower for medium-experienced players, before facing high-level opponents, during later season phases and short recovery cycles (all p < 0.05). Pre-game recovery was lower in centers and high-experience players (p < 0.05). Game performance was better in high-MPG players (p < 0.05) and when facing low and medium-level opponents (p < 0.001). Interestingly, players performed better in games when the previous week’s training load was low (p = 0.042). This study suggests that several individual characteristics and contextual factors need to be considered when monitoring training load (playing experience, playing position, playing time, recovery cycle, upcoming opponent level), recovery (playing experience, playing position) and game performance (opponent level, weekly training load, pre-game recovery) in basketball players during the competitive season.     

Influence of high-intensity interval training on adaptations in well-trained cyclists

The purpose of the present study was to examine the influence of 3 different high-intensity interval training regimens on the first and second ventilatory thresholds (VT(1) and VT(2)), anaerobic capacity (ANC), and plasma volume (PV) in well-trained endurance cyclists. Before and after 2 and 4 weeks of training, 38 well-trained cyclists (Vo(2)peak = 64.5 +/- 5.2 ml.kg(-1).min(-1)) performed (a) a progressive cycle test to measure Vo(2)peak, peak power output (PPO), VT(1), and VT(2); (b) a time to exhaustion test (T(max)) at their Vo(2)peak power output (P(max)); and (c) a 40-km time-trial (TT(40)). Subjects were assigned to 1 of 4 training groups (group 1: n = 8, 8 x 60% T(max) at P(max), 1:2 work-recovery ratio; group 2: n = 9, 8 x 60% T(max) at P(max), recovery at 65% maximum heart rate; group 3: n = 10, 12 x 30 seconds at 175% PPO, 4.5-minute recovery; control group: n = 11). The TT(40) performance, Vo(2)peak, VT(1), VT(2), and ANC were all significantly increased in groups 1, 2, and 3 (p < 0.05) but not in the control group. However, PV did not change in response to the 4-week training program. Changes in TT(40) performance were modestly related to the changes in Vo(2)peak, VT(1), VT(2), and ANC (r = 0.41, 0.34, 0.42, and 0.40, respectively; all p < 0.05). In conclusion, the improvements in TT(40) performance were related to significant increases in Vo(2)peak, VT(1), VT(2), and ANC but were not accompanied by significant changes in PV. Thus, peripheral adaptations rather than central adaptations are likely responsible for the improved performances witnessed in well-trained endurance athletes following various forms of high-intensity interval training programs.     

Discrepancy between cardiorespiratory system and skeletal muscle in elite cyclists after hypoxic training

BACKGROUND: The purpose of this study was to determine the effects of hypoxic training on the cardiorespiratory system and skeletal muscle among well-trained endurance athletes in a randomized cross-over design. METHODS: Eight junior national level competitive cyclists were separated into two groups; Group A trained under normoxic condition (21% O2) for 2 hours/day, 3 days/week for 3 weeks while Group B used the same training protocol under hypoxic condition (15% O2). After 3 weeks of each initial training condition, five weeks of self-training under usual field conditions intervened before the training condition was switched from NT to HT in Group A, from HT to NT in Group B. The subjects were tested at sea level before and after each training period. O2 uptake (O2), blood samples, and muscle deoxygenation were measured during bicycle exercise test. RESULTS AND DISCUSSION: No changes in maximal workload, arterial O2 content, O2 at lactate threshold and O2max were observed before or after each training period. In contrast, deoxygenation change during submaximal exercise in the vastus lateralis was significantly higher at HT than NT (p < 0.01). In addition, half time of oxygenation recovery was significantly faster after HT (13.2 PlusMinus; 2.6 sec) than NT (18.8 PlusMinus; 2.7 sec) (p < 0.001). CONCLUSIONS: Three weeks of HT may not give an additional performance benefit at sea level for elite competitive cyclists, even though HT may induce some physiological adaptations on muscle tissue level.     

Combining explosive and high-resistance training improves performance in competitive cyclists

In several recent studies, athletes experienced substantial gains in sprint and endurance performance when explosive training or high-intensity interval training was added in the noncompetitive phase of a season. Here we report the effect of combining these 2 types of training on performance in the competitive phase. We randomized 18 road cyclists to an experimental (n = 9) or control (n = 9) group for 4-5 weeks of training. The experimental group replaced part of their usual training with twelve 30-minute sessions consisting of 3 sets of explosive single-leg jumps (20 for each leg) alternating with 3 sets of high-resistance cycling sprints (5 x 30 seconds at 60-70 min(-1) with 30-second recoveries between repetitions). Performance measures, obtained over 2-3 days on a cycle ergometer before and after the intervention, were mean power in a 1- and 4-km time trial, peak power in an incremental test, and lactate-profile power and oxygen cost determined from 2 fixed submaximal workloads. The control group showed little mean change in performance. Power output sampled in the training sprints of the experimental group indicated a plateau in the training effect after 8-12 sessions. Relative to the control group, the mean changes (+/-90% confidence limits) in the experimental group were: 1-km power, 8.7% (+/-2.5%); 4-km power, 8.1% (+/-4.1%); peak power, 6.8% (+/-3.6); lactate-profile power, 3.7% (+/-4.8%); and oxygen cost, -3.0% (+/-2.6%). Individual responses to the training were apparent only for 4-km and lactate-profile power (standard deviations of 2.5% and 2.8%, respectively). The addition of explosive training and high-resistance interval training to the programs of already well-trained cyclists produces major gains in sprint and endurance performance, partly through improvements in exercise efficiency and anaerobic threshold.     

Modeling the residual effects and threshold saturation of training: a case study of Olympic swimmers

The aim of this study was to model the residual effects of training on the swimming performance and to compare a model that includes threshold saturation (MM) with the Banister model (BM). Seven Olympic swimmers were studied over a period of 4 +/- 2 years. For 3 training loads (low-intensity w(LIT), high-intensity w(HIT), and strength training w(ST)), 3 residual training effects were determined: short-term (STE) during the taper phase (i.e., 3 weeks before the performance [weeks 0, 1, and 2]), intermediate-term (ITE) during the intensity phase (weeks 3, 4, and 5), and long-term (LTE) during the volume phase (weeks 6, 7, and 8). ITE and LTE were positive for w(HIT) and w(LIT), respectively (p < 0.05). Low-intensity training load during taper was related to performances by a parabolic relationship (p < 0.05). Different quality measures indicated that MM compares favorably with BM. Identifying individual training thresholds may help individualize the distribution of training loads.     

Autoantibodies against oxidized LDL and serum total antioxidant status in active cyclists and ex-cyclists.

There is an apparent paradox between the benefits of aerobic exercise and the potentially deleterious effects of increased free radicals and decreased circulating antioxidants generated during exercise. To assess the oxidative/antioxidative status in competitive cyclists and ex-cyclists, we measured two markers not well studied in these situations, serum total antioxidant status (TAS) and antibodies against oxidized LDL (AuAb-ox-LDL) in 18 competitive male cyclists, 10 ex-competitive cyclists and 14 healthy males. AuAb-ox-LDL was evaluated by enzyme immunoassay, and serum TAS concentration was analyzed by spectrophotometry. Ex-cyclists had serum TAS levels statistically higher than the control group and cyclists group (p = 0.001 and p < 0.001, respectively). Active sportsmen showed significantly less AuAb-ox-LDL than healthy sedentary males, while there was a non-significant trend in the ex-cyclists to have lower AuAb-ox-LDL than the corresponding control group. AuAb-ox-LDL levels were not statistically different between the groups of active and previously active sporting men. There was a positive correlation between TAS and LDL-cholesterol in active cyclists under heavy training. In the ex-cyclist group, there was a negative correlation between serum TAS and the time elapsed since they had ended the competition. Competitive cycling decreases AuAb-ox-LDL levels, suggesting that it may decrease ox-LDL levels. After ending physical training, antioxidative status remains increased for at least one year, but the effect on AuAb-ox-LDL levels is lost.     

Airborne Pinus pollen in the atmosphere of Brisbane, Australia and relationships with meteorological parameters

Relationships between weather parameters andairborne pollen loads of Pinus inBrisbane, Australia have been investigated overthe five-year period, June 1994–May 1999.Pinus pollen accounts for 4.5% of the annualairborne pollen load in Brisbane where thePinus season is confined to the winter months,July–early September. During the samplingperiod loads of 11–>100 grains m³ wererecorded on 24 days and 1–10 grains m³ on204 days. The onset and peak dates wereconsistent across each season, whereas the enddates varied. The onset of the Pinuspollen season coincided with the coolestaverage monthly temperatures (< 22°C),lowest rainfall (< 7mm), and four weeks afterdaily minimum temperatures fell to 5–9°Cin late autumn. Correlations obtained betweendaily airborne Pinus pollen counts andtemperature/rainfall parameters show thatdensities of airborne Pinus pollen arenegatively correlated with maximum temperature(p < 0.0001), minimum temperature (p < 0.0001)and rainfall (p < 0.05) during the mainpollination period. The mean duration of eachpollen season was 52 days; longer seasons wereshown to be directly related to lower averageseasonal maximum temperatures (r² = 0.85,p = 0.025). These results signify that maximumand minimum temperatures are the majorparameters that influence the onset andduration of the Pinus pollen season inthe environs of Brisbane. Respiratory allergyis an important health issue in Brisbane,Australia, but it remains unknown whether ornot airborne Pinus pollen is acontributing factor.     

Impact of training patterns on incidence of illness and injury during a women's collegiate basketball season

This study was conducted to monitor the training patterns throughout a basketball season in order to determine if a relationship exists between the physical stress of practice and the occurrence of injuries and illnesses in NCAA Division III athletes. Subjects consisted of college women (n = 12) ranging in age from 18 to 22 years. A certified athletic trainer distributed a questionnaire following each practice, including 2 weeks of preseason, documenting the presence of injury, illness, or both, relative to the intensity and duration of practice. Training load, training monotony, and training strain were computed using the session rate of perceived exertion scale method. An increase in injuries occurred during times of increased training loads, particularly during the first 2 weeks of formal practice, and immediately subsequent to the holidays. The temporal relationship between training load and injury suggests a causative link (p < 0.01; r = 0.675). The present data suggest that the periodization pattern of basketball training may be linked to the likelihood of illness/injury.     

Throwing velocities, anthropometric characteristics, and efficacy indices of women's European water polo subchampions

Water polo is a team sport characterized by a high-intensity, intermittent activity, where technical and tactical aspect are of a great importance. For that reason, the main aim of this study was to define the anthropometrical characteristics, maximum isometric grip strength, training and competition throwing velocities, and the efficacy indices in female high-level water polo players. A second purpose was to examine the differences between the throwing velocities in training vs. European championships in the water polo female national team. Ten elite trained female water polo players participated in this study. Before the competitive phase of their season, the following measures were taken: standard anthropometry, static and dynamic training throwing velocities, and hand-grip dynamometry. In the competitive phase, efficacy indices, average and maximum throwing velocities from all the participants were also determined. Significant differences (p ≤ 0.05) were found between different training situations and different competitive throwing velocities. We concluded that elite female water polo players modify their throwing velocity depending if the throw is performed during training or competitive situation.     

MONITORING TRAINING LOADS,STRESS, IMMUNE-ENDOCRINE RESPONSES AND PERFORMANCE IN TENNIS PLAYERS

The study aim was to investigate the effect of a periodised pre-season training plan on internal training load and subsequent stress tolerance, immune-endocrine responses and physical performance in tennis players. Well-trained young tennis players (n = 10) were monitored across the pre-season period, which was divided into 4 weeks of progressive overloading training and a 1-week tapering period. Weekly measures of internal training load, training monotony and stress tolerance (sources and symptoms of stress) were taken, along with salivary testosterone, cortisol and immunoglobulin A. One repetition maximum strength, running endurance, jump height and agility were assessed before and after training. The periodised training plan led to significant weekly changes in training loads (i.e. increasing in weeks 3 and 4, decreasing in week 5) and post-training improvements in strength, endurance and agility (P < 0.05). Cortisol concentration and the symptoms of stress also increased in weeks 3 and/or 4, before returning to baseline in week 5 (P < 0.05). Conversely, the testosterone to cortisol ratio decreased in weeks 3 and 4, before returning to baseline in week 5 (P < 0.05). In conclusion, the training plan evoked adaptive changes in stress tolerance and hormonal responses, which may have mediated the improvements in physical performance.     

Changes in muscle architecture and performance during a competitive season in female softball players

ABSTRACT: Nimphius, S, McGuigan, MR, and Newton, RU. Changes in muscle architecture and performance during a competitive season in female softball players. J Strength Cond Res 26(10): 2655-2666, 2012-The purpose of this research was (a) to examine the performance changes that occur in elite female softball players during 20 weeks of softball training (that included 14 weeks of periodized resistance training [RT]) and (b) to examine the relationship between percent change (%change) in muscle architecture variables and %change in strength, speed, and change of direction performance. Ten female softball players (age = 18.1 ± 1.6 years, height = 166.5 ± 8.9 cm, weight = 72.4 ± 10.8 kg) from a state Australian Institute of Sport softball team were tested for maximal lower-body strength using a 3 repetition maximum for a predicted 1 repetition maximum (1RM) and peak force, peak velocity (PV), and peak power (PP) were measured during jump squats (JS) unloaded and loaded. In addition, the first base (1B) and the second base (2B) sprint performance, change of direction (505) on dominant (D) and nondominant (ND) sides, aerobic capacity, and muscle architecture characteristics of vastus lateralis (VL) including muscle thickness (MT), fascicle length (FL), and pennation angle (θp) were examined. The testing sessions occurred pre, mid, and post training (total 20 week pre- and in-season training period). Changes over time were analyzed by repeated-measures analysis of variance. The relationship between %change in muscle architecture variables and strength, speed, and change of direction variables from pre to post were assessed by Pearson product-moment correlation coefficient. Significant improvements in PV and PP occurred at all JS loads pre- to mid-testing and pre- to post-testing. Significant increases occurred pre-post in absolute 1RM, relative 1RM, 505 ND, and 2B sprint. The strongest relationships were found between %change in VL MT and 1B sprint (r = -0.80, p = 0.06), %change in VL FL and 2B sprint (r = -0.835, p = 0.02), and %change in relative 1RM and 505 D (r = -0.70, p = 0.04). In conclusion, gains in strength, power, and performance can occur during the season in elite softball players who are also engaged in a periodized RT program. Furthermore, changes in performance measures are associated with changes in muscle architecture.     

Resistin, visfatin and insulin sensitivity in selected phases of annual training cycle of triathletes

The purpose of the study was to examine the effects of sport training on carbohydrate metabolic indices and adipokines concentrations in young male triathletes (n=10). Athletes performed the incremental running test in two periods of the training cycle: in the transitory and preparatory phases. In both analyzed terms, physical exercise was reflected by a significant increase in lactate (p≤0.01), insulin (p≤0.01), visfatin concentrations (p≤0.01, p<0.05, respectively) and only during transitory phase in glucose (p≤0.01) and resistin concentrations (p<0.05). Significant inter-period differences were noted in the pre-exercise insulin (p≤0.01) and also in pre- and post-exercise visfatin concentrations (p<0.05). Additionally, the differences (Δ) between post- and pre-exercise values of glucose (p<0.05) and visfatin (p≤0.01) significantly decreased in the preparatory phase comparing to the transitory phase. The inverse correlations between pre-exercise concentrations of visfatin and peak oxygen uptake (p<0.05) in the transitory phase and between post- and pre-exercise differences (Δ) of visfatin and lactate concentrations (p<0.05) in the preparatory phase were noted. During preparatory phase, pre-exercise visfatin concentrations inversely correlated with pre-exercise resistin, insulin and glucose levels (p<0.05). In conclusion, systematic training in elite triathletes modulates basal adipokine concentrations only to a small extent, however, influences on these molecules response on the acute exercise.     

Changes in physiological and anthropometric characteristics of rugby league players during a competitive season

This study investigated the physiological and anthropometric characteristics of rugby league players during a competitive season. Sixty-eight rugby league players were allocated into training (n = 52) and nonexercise control (n = 16) groups. The training group participated in 2 field-training sessions per week, with training loads, match loads, and injury rates recorded. Subjects performed measurements of standard anthropometry (height, body mass, and sum of 7 skinfolds), muscular power (vertical jump), speed (10-, 20-, and 40-m sprint), agility (L run), and maximal aerobic power (multistage fitness test) in December (off-season), March (preseason), May (midseason), and August (end season). Increases in maximal aerobic power and muscular power and reductions in skinfold thickness were observed during the early phases of the season when training loads were highest. However, reductions in muscular power and maximal aerobic power and increases in skinfold thickness occurred toward the end of the season, when training loads were lowest and match loads and injury rates were highest. These findings suggest that high overall playing intensity and match loads in end-season matches increase in injury rates in the latter half of the season, and residual fatigue associated with limited recovery between successive matches may compromise the physical development of rugby league players.     

Serum thyroid hormones, thyrotropin and thyroxine binding globulin during prolonged strength training

The effects of progressive strength training for 24 weeks on maximal strength and pituitary-thyroid function were studied in 21 males during the training and during the following detraining period of 12 weeks. Maximal strength increased greatly (p less than 0.001) in the first 20 weeks, followed by a plateau phase in the last 4 weeks of training. Maximal strength decreased greatly (p less than 0.001) during the detraining period. The concentrations of serum total (T4) and free thyroxine (fT4) decreased (p less than 0.05 and less than 0.01, respectively) during the training period and they rose to pretraining levels during the detraining period. During the most intense training phase (the last 4 weeks) there was a positive correlation between the changes in serum fT4 concentrations and the changes in maximal force (r = 0.56; p less than 0.01). No statistically significant changes occurred in the levels of serum triiodothyronine, thyrotropin or thyroxine binding globulin. The results show that prolonged intensified strength training can slightly decrease the concentrations of serum total and free T4. These small changes cannot have any clinical significance, and even their physiological significance may be only marginal.     

Effects of in-season strength maintenance training frequency in professional soccer players

The aim of the present study was to examine the effect of in-season strength maintenance training frequency on strength, jump height, and 40-m sprint performance in professional soccer players. The players performed the same strength training program twice a week during a 10-week preparatory period. In-season, one group of players performed 1 strength maintenance training session per week (group 2 + 1; n = 7), whereas the other group performed 1 session every second week (group 2 + 0.5; n = 7). Only the strength training frequency during the in-season differed between the groups, whereas the exercise, sets and number of repetition maximum as well as soccer sessions were similar in the 2 groups. The preseason strength training resulted in an increased strength, sprint, and jump height (p < 0.05). During the first 12 weeks of the in-season, the initial gain in strength and 40-m sprint performance was maintained in group 2 + 1, whereas both strength and sprint performance were reduced in group 2 + 0.5 (p < 0.05). There was no statistical significant change in jump height in any of the 2 groups during the first 12 weeks of the in-season. In conclusion, performing 1 weekly strength maintenance session during the first 12 weeks of the in-season allowed professional soccer players to maintain the improved strength, sprint, and jump performance achieved during a preceding 10-week preparatory period. On the other hand, performing only 1 strength maintenance session every second week during the in-season resulted in reduced leg strength and 40-m sprint performance. The practical recommendation from the present study is that during a 12-week period, 1 strength maintenance session per week may be sufficient to maintain initial gain in strength and sprint performance achieved during a preceding preparatory period.     

Whichever the initial training status,any increase in velocity at lactate threshold appears as a major factor in improved time to exhaustion at the same severe velocity after training

The first purpose of this study was to assess the eventual training adaptations in the time to exhaustion at the same severe velocity occurring after severe interval-training programs in few- and well-trained subjects. In the event of such training adaptations, the second purpose was to identify the discriminant factors of performance improvement according to the initial training status. Seven few- and six well-trained subjects performed: firstly, an incremental test to determine the maximal oxygen consumption (VO2max), the energy cost of running (ECR), the velocity associated with the achievement of VO2max (vVO2max) and the lactate threshold (LT expressed in VO2, km x h(-1), % vVO2max); secondly, an all-out test at the velocity corresponding to the midway between vLT and vVO2max (vdelta50) to determine the time to exhaustion (tmax); such tests were carried out before and after 4- and 8-week severe interval-training programs. In the few-trained subjects, all factors of performance (i.e., VO2max, ECR, vVO2max, LT expressed in VO2, km x h(-1), % vVO2max) and tmax at the pre-training vdelta50 were improved after training (+8, -8, +7, +9, +14, +6% and +79%, respectively); only the increase in vLT was related to the one in tmax (r = 0.714, p < or = 0.05, n = 7). In the well-trained subjects, only vVO2max was improved (+3%) due to the decrease in ECR (-3%), tmax at the pre-training vdelta50 did not vary after training; only the three subjects (over six) who improved their vLT (+0.5, +0.5, +0.8 km x h(-1), respectively) improved their tmax (+10, +24, +101%, respectively) (r = 0.895, p < or = 0.01, n = 6). So, whichever the initial training status, any training-induced adaptation in vLT appeared as a major factor of performance improvement especially at supra-LT velocities.     

The IGF-1/cortisol ratio as a useful marker for monitoring training in young boxers

Training effects on plasma insulin-like growth factor-1 (IGF-1)/cortisol ratio were investigated in boxers. Thirty subjects were assigned to either the training or the control group (n = 15 in both). They were tested before the beginning of training (T0), after 5 weeks of intensive training (T1), and after 1 week of tapering (T2). Physical performances (Yo-Yo intermittent recovery test level-1), training loads, and blood sampling were obtained at T0, T1, and T2. Controls were only tested for biochemical and anthropometric parameters at T0 and T2. A significantly higher physical performance was observed at T2 compared to T1. At T1, cortisol levels were significantly increased whereas IGF-1 and insulin-like growth factor binding protein-3 (IGFBP-3) levels remained unchanged compared to baseline. At T2, cortisol levels decreased while IGF-1 and IGFBP-3 levels increased. The IGF-1/cortisol ratio decreased significantly at T1 and increased at T2, and its variations were significantly correlated with changes in training loads and Yo-Yo intermittent recovery test level 1 (IRT1) performance over the training period. Cortisol variations correlated with changes in training load (r = 0.64; p < 0.01) and Yo-Yo IRT1 performance (r = 0.78; p < 0.001) at T1 whereas IGF-1 variations correlated only with changes in Yo-Yo IRT1 performance at T2 (r = 0.71; p < 0.001). It is concluded that IGF-1/cortisol ratio could be a useful tool for monitoring training loads in young trained boxers.