Neuromuscular and cardiovascular adaptations during concurrent strength and endurance training in untrained men

This study examined the effects of concurrent strength and endurance training on neuromuscular and endurance characteristics compared to strength or endurance training alone. Previously untrained men were divided into strength (S: n=16), endurance (E: n=11) or concurrent strength and endurance (SE: n=11) training groups. S and E trained 2 times and SE 2 + 2 times a week for strength and endurance during the 21-week period. Maximal unilateral isometric and bilateral concentric forces of leg muscles increased similarly in S and SE by 20-28% (p<0.01) and improvements in isometric forces were accompanied by increases (p<0.05) of maximal muscle activation. Rate of force development of isometric action (p<0.05) improved only in S. The increase in muscle cross-sectional area of the quadriceps femoris in SE (11%, p<0.001) were greater than in S (6%, p<0.001) or in E (2%, p<0.05). SE and E increased maximal cycling power (SE: 17% and E: 11%, p<0.001) and VO2MAX (SE: 17%, p<0.001 and E: 5%, ns.). These results suggest that the present moderate volume 21-week concurrent SE training in previously untrained men optimizes the magnitude of muscle hypertrophy, maximal strength and endurance development, but interferes explosive strength development, compared with strength or endurance training alone.     

Physiological performance capacity in different prepubescent athletic groups

Endurance, strength and speed capacity were investigated among prepubescent male weight lifters (EL), endurance runners (ER) and sprint runners (SR). The subjects were selected by their coaches and all of them were classified as promising and successful junior athletes in the age groups of 10-13 years. Twelve boys belonged to athletic group (AG) and their performance capacity was compared to normally active control (C) boys (n = 9). Biological age was significantly (p less than 0.05) greater in AG (11.3 +/- 0.9 years) than in C (10.2 +/- 1.4 years) but in chronological age there was no difference between the groups. Maximal oxygen uptake was significantly (p less than 0.05) higher in AG (62.3 +/- 3.1 ml.kg-1.min-1) than in C (55.4 +/- 7.7 ml.kg-1.min-1). The endurance runners had the highest value (66.5 +/- 2.9 ml.kg-1.min-1). In anaerobic characteristics there were no significant differences. The rise of centre of gravity (0.26 +/- 0.03 m) of AG in a test for the best drop jump was clearly (p less than 0.05) higher than that (0.22 +/- 0.03 m) of C. The weight lifters and sprint runners were the best in the test for force production. AG had significantly (p less than 0.01) shorter choice reaction time (261 +/- 39 ms) than C (344 +/- 81 ms). Testosterone correlated with jump performances (p less than 0.05), biological age (p less than 0.01) and chronological age (p less than 0.001). Growth hormone correlated significantly only with biological age (p less than 0.05) and testosterone (p less than 0.001). In conclusion, endurance capacity (aerobic) and strength capacity were greater in the athletic group than in the control group and it was suggested that training background and more advanced biological maturation of the athletes affected especially their strength capacity. The parameters used in this investigation can be utilized for talent selection in sport.     

Optimizing strength training for running and cycling endurance performance: A review

Here we report on the effect of combining endurance training with heavy or explosive strength training on endurance performance in endurance‐trained runners and cyclists. Running economy is improved by performing combined endurance training with either heavy or explosive strength training. However, heavy strength training is recommended for improving cycling economy. Equivocal findings exist regarding the effects on power output or velocity at the lactate threshold. Concurrent endurance and heavy strength training can increase running speed and power output at VO_2max (V_max and W_max, respectively) or time to exhaustion at V_max and W_max. Combining endurance training with either explosive or heavy strength training can improve running performance, while there is most compelling evidence of an additive effect on cycling performance when heavy strength training is used. It is suggested that the improved endurance performance may relate to delayed activation of less efficient type II fibers, improved neuromuscular efficiency, conversion of fast‐twitch type IIX fibers into more fatigue‐resistant type IIA fibers, or improved musculo‐tendinous stiffness.     

Weight lifting training and left ventricular function in adolescent subjects

AIM: Training during adolescence may influence the myocardium's adaptation. Effects of exercise training on left ventricular function differ depending whether they result from pressure or volume overload. Accordingly, the present study was designed to examine, by echocardiography studies, the effects of endurance versus weight lifting training modes on left ventricular contractility in healthy adolescent boys. METHODS: Sixty healthy adolescent boys were randomly and evenly divided into 3 groups: weightlifting training, run-training, and control. Exercising groups underwent 28-week training programs, 3-4 times a week, 35 min each session. The weight lifting program for consisted of training on 6 dynamic resistive machines at resistance corresponding to 6-repetition maximum. The running program was composed of aerobic exercise training at 65% of their VO(2max). RESULTS: At rest, only in the runners end diastolic volume and end systolic pressure-volume ratio differed significantly (P<0.05) from pre- to post-testing. During post-testing session at peak exercise, runners compared to weightlifters demonstrated improvement respectively in: wall stress (245+/-42 and 290+/-35 103 dyn.cm(2)), end systolic pressure-volume ratio (7.2+/-.7 and 6.4+/-.5 ratio) and ejection fraction (82+/-5% and 76+/-5%). Maximal oxygen uptake (48.2+/-3.2 and 43.8+/-3.5 mL.kg(-1).min(-1)), also improved significantly (P<0.05). Maximal load was significantly (P<0.05) higher in the runners and weight lifters than in the control group with significantly (P<0.05) higher values for the weight lifters than runners. CONCLUSION: This study has showed that in adolescent boys the mode of exercise training leads to significant differences in left ventricular function and contractility, related to differences in volume-after-load relationship and not to fundamental differences in the properties of the myocardium.     

The impact of resistance training on distance running performance

Traditionally, distance running performance was thought to be determined by several characteristics, including maximum oxygen consumption (VO(2max)), lactate threshold (LT), and running economy. Improvements in these areas are primarily achieved through endurance training. Recently, however, it has been shown that anaerobic factors may also play an important role in distance running performance. As a result, some researchers have theorised that resistance training may benefit distance runners. Because resistance training is unlikely to elicit an aerobic stimulus of greater than 50% of VO(2max), it is unlikely that resistance training would improve VO(2max) in trained distance runners. However, it appears that VO(2max) is not compromised when resistance training is added to an endurance programme. Similarly, LT is likely not improved as a result of resistance training in trained endurance runners; however, improvements in LT have been observed in untrained individuals as a result of resistance training. Trained distance runners have shown improvements of up to 8% in running economy following a period of resistance training. Even a small improvement in running economy could have a large impact on distance running performance, particularly in longer events, such as marathons or ultra-marathons. The improvement in running economy has been theorised to be a result of improvements in neuromuscular characteristics, including motor unit recruitment and reduced ground contact time. Although largely theoretical at this point, if resistance training is to improve distance running performance, it will likely have the largest impact on anaerobic capacity and/or neuromuscular characteristics. The primary purpose of this review is to consider the impact of resistance training on the factors that are known to impact distance running performance. A second purpose is to consider different modes of resistance exercise to determine if an optimal protocol exists.     

Changes in aerobic and anaerobic fitness in the Polish army paratroopers during their military service

BACKGROUND: The purpose of this study was to estimate changes in the aerobic- and anaerobic-dependent performance tasks in paratroopers during 18 mo of their military service. METHODS: There were 39 Polish Army recruits, enlisted to the paratroops, who volunteered for this study. The subjects were examined on enlisting and then after 3, 12, and 18 mo of the service. Anthropometry, aerobic capacity (V(O2max), V(O2OBLA), PWC170), anaerobic power and capacity (using Wingate test), performance in the repeated supramaximal exercises and motor performance indices (battery tests for locomotory endurance, agility, explosive power, strength and muscular endurance) were assessed. RESULTS: Military training produced a significant (p) < 0.05) increase in the body weight (by 4%), lean body mass (by 5.7%) and selected body girths. This was associated by the decrease in body fat from 15% to 13.1%). No significant changes in the aerobic fitness indices were noted. The studied soldiers showed significant increases in anaerobic power (by 5.9%) and anaerobic capacity (by 9.7%) accompanied by a substantial improvement in the performance in the repeated supramaximal exercises. There were also striking improvements in the variables which reflected muscular endurance and explosive power (by 32 78%), a substantial increase in the variables which reflected locomotory endurance (by 12.4%), agility (by 13.7%) and speed (by 11%), and a small rise in the static strength (by 4%). CONCLUSIONS: Overall, the present results show that the military training for paratroopers improves the motor performance and the anaerobic-dependent performance tasks and leads to favorable changes in the body composition but does not result in the improvement of aerobic fitness.     

31P-MRS characterization of sprint and endurance trained athletes

Muscle metabolism and force production were studied in sprint trained runners, endurance trained runners and in untrained subjects, using 31P-MRS. 31P-spectra were obtained at a time resolution of 5 s during four maximal isometric contractions of 30-sec duration, interspersed by 60-sec recovery intervals. Resting CrP/ATP ratio averaged 3.3 +/- 0.3, with no difference among the three groups. The sprint trained subjects showed about 20 % larger contraction forces in contraction bouts 1 and 2 (p < 0.05). The groups differed with respect to CrP breakdown (p < 0.05), with sprinters demonstrating about 75 % breakdown in each contraction compared to about 60 % and 40 % for untrained and endurance trained subjects, respectively (p < 0.05). The endurance trained runners showed almost twice as fast CrP recovery (t 1/2 = 12.5 +/- 1.5) compared to sprint trained (t 1/2 = 22.5 +/- 2.53) and untrained subjects (t 1/2 = 26.4 +/- 2.8). From the initial rate of CrP resynthesis the rate of maximal aerobic ATP synthesis was estimated to 0.74 +/- 0.07, 0.73 +/- 0.10 and 0.33 +/- 0.07 mmol ATP x kg -1 wet muscle x sec -1 for sprint trained, endurance trained and untrained subjects, respectively. Only the sprint trained and the untrained subjects displayed a significant drop in pH and only during the first of the four contractions, about 0.2 and 0.1 pH units, respectively, indicating that only under those contractions was the glycolytic proton production larger than the proton consumption by the CK reaction. Also, in the first contraction the energy cost of contraction was higher for the sprinters compared to the two other groups. The simple 31P-MRS protocol used in the present study demonstrates marked differences in force production, aerobic as well as anaerobic muscle metabolism, clearly allowing differentiation between endurance trained, sprint trained and untrained subjects.     

Difference in mechanical and energy cost between highly, well, and nontrained runners

INTRODUCTION: Recently it has been shown that endurance training decreases the variability in stride rate. This decrease would lead to a reduction in the mechanical and the energy cost of running. PURPOSE: This study therefore aimed to compare the mechanical and the energy cost of running according to the training status of the runner (highly, well, and nontrained endurance runners). METHODS: The kinetic, potential, and internal mechanical costs (Cke, Cpe, and Cint) were measured with a 3D motion analysis system (ANIMAN3D). The energy cost of running (C) was measured from pulmonary gas exchange using a breath-by-breath portable gas analyser (Cosmed K4b2, Rome, Italy). All the parameters were measured on track, for a speed of 4.84 +/- 0.36 m x s(-1). RESULTS: Highly trained runners did not exhibit significantly lower C compared with well or nontrained runners (4.46 +/- 0.38; 4.33 +/- 0.32; 4.46 +/- 0.46 J x kg(-1) x m(-1), respectively; P = 0.75). However, Cpe was significantly lower in highly and well-trained runners compared with nontrained runners (0.43 +/- 0.07; 0.45 +/- 0.05; 0.54 +/- 0.08 J x kg(-1) x m(-1), respectively; P < 0.05). In contrast, Cint was significantly higher in highly trained runners compared with well and nontrained runners (respectively, 0.80 +/- 0.12; 0.60 +/- 0.09; 0.59 +/- 0.10 J x kg(-1) x m(-1); P < 0.05). CONCLUSION: Although there is a significant difference in Cpe and in Cint between runners of various training status, there is no difference in C. Differences in Cpe and Cint may be associated with the same self-optimizing mechanism that contributes to a reduction in the impact loads during the initial portion of the support phase of the stride.     

Effects of resistance training on endurance capacity and muscle fiber composition in young top-level cyclists

Equivocal findings exist on the effect of concurrent strength (S) and endurance (E) training on endurance performance and muscle morphology. Further, the influence of concurrent SE training on muscle fiber-type composition, vascularization and endurance capacity remains unknown in top-level endurance athletes. The present study examined the effect of 16 weeks of concurrent SE training on maximal muscle strength (MVC), contractile rate of force development (RFD), muscle fiber morphology and composition, capillarization, aerobic power (VO2max), cycling economy (CE) and long/short-term endurance capacity in young elite competitive cyclists (n=14). MVC and RFD increased 12-20% with SE (P<0.01) but not E. VO2max remained unchanged. CE improved in E to reach values seen in SE. Short-term (5-min) endurance performance increased (3-4%) after SE and E (P<0.05), whereas 45-min endurance capacity increased (8%) with SE only (P<0.05). Type IIA fiber proportions increased and type IIX proportions decreased after SE training (P<0.05) with no change in E. Muscle fiber area and capillarization remained unchanged. In conclusion, concurrent strength/endurance training in young elite competitive cyclists led to an improved 45-min time-trial endurance capacity that was accompanied by an increased proportion of type IIA muscle fibers and gains in MVC and RFD, while capillarization remained unaffected.     

Concurrent training with different aerobic exercises

The aim of the present study was to compare the effects of using different intensities and types of aerobic exercise (i. e., cycle ergometer or running) during concurrent training on neuromuscular adaptations. A total of 44 young women were randomly assigned to 1 of 4 groups: concurrent strength and continuous running training (SCR, n=10), concurrent strength and interval running training (SIR, n=11), concurrent strength and continuous cycle ergometer training (SCE, n=11), or strength training only (STO, n=12). Each group trained twice a week during 11 weeks. The following strength measurements were made on all subjects before and after training period: maximal strength (1RM) in knee extension, bench press and leg press exercises; local muscular endurance (number of repetitions at 70% of 1 RM) in knee extension and bench press exercises; and isometric and isokinetic peak torque of knee extension. There were significant increases in the upper and lower-body 1 RM, isometric and isokinetic peak torque in all training groups (p<0.001), with no differences between groups. The present results suggest that in young women, concurrent training performed twice a week promotes similar neuromuscular adaptations to strength training alone, regardless of the type and the intensity in which the aerobic training is performed.     

Effects of strength training on running economy

The objective of this study was to compare the effect of different strength training protocols added to endurance training on running economy (RE). Sixteen well-trained runners (27.4 +/- 4.4 years; 62.7 +/- 4.3 kg; 166.1 +/- 5.0 cm), were randomized into two groups: explosive strength training (EST) (n = 9) and heavy weight strength training (HWT) (n = 7) group. They performed the following tests before and after 4 weeks of training: 1) incremental treadmill test to exhaustion to determine of peak oxygen uptake and the velocity corresponding to 3.5 mM of blood lactate concentration; 2) submaximal constant-intensity test to determine RE; 3) maximal countermovement jump test and; 4) one repetition maximal strength test in leg press. After the training period, there was an improvement in RE only in the HWT group (HWT = 47.3 +/- 6.8 vs. 44.3 +/- 4.9 ml . kg (-1) . min (-1); EST = 46.4 +/- 4.1 vs. 45.5 +/- 4.1 ml . kg (-1) . min (-1)). In conclusion, a short period of traditional strength training can improve RE in well-trained runners, but this improvement can be dependent on the strength training characteristics. When comparing to explosive training performed in the same equipment, heavy weight training seems to be more efficient for the improvement of RE.     

Specificity of endurance, sprint and strength training on physical performance capacity in young athletes

Three prebubescent athlete groups of endurance runners (E; n = 4), sprinters (S; n = 4) and weightlifters (WL; n = 4) and one control group (C; n = 6) as well as one junior but postpubescent weightlifter group (JWL; n = 6) volunteered as subjects in order to investigate specific effects of endurance, sprint and strength training on physical performance capacity during a 1 year follow-up period. The prepubescent E-group had higher (p less than 0.05) VO2 max (66.5 +/- 2.9 ml x kg1 x min-1) already at the beginning of the study than the other three groups. The prepubescent WL-group demonstrated greater (p less than 0.05) maximal muscular strength than the E-group and the WL-group increased its strength greatly by 21.4% (p less than 0.05) during the follow-up. No significant differences were observed in physical performance capacity between the prepubescent WL- and S-groups. Both groups demonstrated a slightly (ns.) better force-time curve recorded from the leg extensor muscles than the E-group and significant (p less than 0.05) increases occurred in these two groups in dynamic explosive performance during the follow-up. The postpubescent JWL-group demonstrated much greater (p less than 0.001) muscular mass and maximal strength than the prepubescent groups. No significant changes occurred in explosive types of performances in these athletes but significant (p less than 0.05) increase took place in the maximal neural activation and strength of the leg extensor muscles during the 1 year.(ABSTRACT TRUNCATED AT 250 WORDS)     

Slow component of VO(2) during level and uphill treadmill running: relationship to aerobic fitness in endurance runners

AIM: The aim of this study was to compare the oxygen uptake (VO(2)) slow component (SC) during level and uphill running in endurance runners, and to identify associations between the SC and the following aerobic fitness indicators: peak VO(2), running speed associated with the peak VO(2) (Vpeak), running speed at the lactic threshold and the VO(2) fraction elicited at the lactic threshold. METHODS: Fourteen male endurance-trained runners underwent several 6-min bouts of level (LTR) and 10.5% uphill treadmill running. VO(2) SC was calculated as the difference between mean VO(2) during the 6th and the 3rd minutes. RESULTS: The highest mean values for the SC were 181.9+/-240.2 mL x min(-1) for level running at approximately 94% peak VO(2)2 and 105.4+/-154.6 mL x min(-1) for uphill running at approximately 90% peak VO(2). The SC observed during the last bout of the LTR correlated with peak VO(2) and with Vpeak (-0.71 and -0.76, P<0.05, respectively). CONCLUSION: The results show that for endurance-trained runners the magnitude of the SC is not affected by the treadmill gradient and that within a homogeneous sample of endurance-trained runners the SC does not correlate with indicators of aerobic fitness.     

Factors related to top running speed and economy

The main purpose of the present study was to investigate the relationships between running mechanics, top running speed and economy in young endurance athletes. Twenty five endurance athletes (age 19.8 +/- 1.1 years, stature 1.82 +/- 0.07 m and body mass 69.4 +/- 7.5 kg) performed two separate tests on an indoor track. The first test was 8 x 30 m with increasing speed, and the second test was incremental 5 - 6 x 1,000 m. In the first test, ground reaction forces and stride characteristics were measured from each running speed. In the second test, running economy at the speed of 3.89 m . s (-1) and maximal oxygen uptake were determined. Ground contact time was the only factor which correlated significantly with both running economy (r = 0.49, p < 0.05) and maximal running speed (r = - 0.52, p < 0.01). Furthermore, maximal running speed was correlated significantly with the mass-specific horizontal force (r = 0.56, p < 0.01) but not with the vertical effective force. It is concluded that the short contact times required in economical and high speed running suggests that fast force production is important for both economical running and high top running speed in distance runners.     

The effect of high-intensity rowing and combined strength and endurance training on left ventricular systolic function and morphology

Combined strength and endurance training may result in alterations in left ventricular (LV) systolic function and morphology, however, the acute effect of high-intensity rowing exercise and concurrent training-induced adaptations on LV systolic function are not well known. The purpose of this investigation was to assess LV systolic function before and after a simulated 2000-m rowing race on a Concept II rowing ergometer and evaluate these adaptations following 10 weeks of concurrent strength and endurance training. Furthermore, resting LV morphology was assessed prior to and following the 10-week training program. Ten male subjects underwent two-dimensional echocardiograms at rest, immediately following (95 +/- 27 s), as well as 5 and 45 minutes after, a simulated 2000-m rowing race. These measurements were also made before and after 10 weeks of training. Irrespective of testing time, performance of a 2000-m rowing race resulted in an increase in fractional area change (0.51 +/- 0.06 vs. 0.63 +/- 0.09; p < 0.05) due to an increase in LV contractility. Concurrent strength and endurance training resulted in an increase in the resting LV diastolic cavity area (20.64 +/- 2.59 vs. 22.82 +/- 2.17 cm (2); p < 0.05), end systolic myocardial area (23.27 +/- 4.86 vs. 24.56 +/- 4.00 cm (2); p < 0.05) and LV mass (179.07 +/- 46.91 g vs. 210.46 +/- 51.13 g; p < 0.05). These findings suggest that the acute increase in LV systolic function following a simulated 2000-m rowing race was due to heightened LV contractile reserve. Further, 10 weeks of combined strength and endurance training resulted in an increase in resting LV diastolic cavity size, wall thickness and mass.     

Lactate and glucose minimum speeds and running performance

This study aimed to analyse the validity of glucose minimum speed (GMS) for lactate minimum speed (LMS) assessment during running and their relationship to endurance performance. Eight male trained runners (28.7 +/- 9.0 years) volunteered to take part in this study and underwent an official 10-km road race and a track lactate minimum test (LMT) (0.5-km sprint plus 6 x 800 m from 87 to 98% of maximal 3-km speed). Lactate and glucose minimum speeds were considered those related to the minimum blood lactate and glucose concentrations respectively attained during the graded phase of LMT. Significant correlations (p < 0.05) were found between LMS and GMS (r = 0.72) and LMS and 10-km performance (r = 0.83), but not between GMS and 10-km performance (r = 0.49). No significant differences (p > 0.05) were found between LMS (4.75 +/- 0.08 m/s), GMS (4.73 +/- 0.07 m/s) and 10-km mean speed (4.79 +/- 0.17 m/s). In conclusion, we found GMS to be a good predictor of LMS during track LMT, LMS being well related to endurance running performance.     

Effect of the passive recovery period on the lactate minimum speed in sprinters and endurance runners

The objective of this study was to verify the effect of the passive recovery time following a supramaximal sprint exercise and the incremental exercise test on the lactate minimum speed (LMS). Thirteen sprinters and 12 endurance runners performed the following tests: (1) a maximal 500 m sprint followed by a passive recovery to determine the time to reach the peak blood lactate concentration; (2) after the maximal 500 m sprint, the athletes rested eight mins, and then performed 6 x 800 m incremental test, in order to determine the speed corresponding to the lower blood lactate concentration (LMS1) and; (3) identical procedures of the LMS1, differing only in the passive rest time, that was performed in accordance with the time to peak lactate (LMS2). The time (min) to reach the peak blood lactate concentration was significantly higher in the sprinters (12.76 +/- 2.83) than in the endurance runners (10.25 +/- 3.01). There was no significant difference between LMS 1 and LMS2, for both endurance (285.7 +/- 19.9; 283.9 +/- 17.8 m/min; r = 0.96) and sprint runners (238.0 +/- 14.1; 239.4 +/- 13.9 m/min; r = 0.93), respectively. We can conclude that the LMS is not influenced by a passive recovery period longer than eight mins (adjusted according with the time to peak blood lactate), although blood lactate concentration may differ at this speed. The predominant type of training (aerobic or anaerobic) of the athletes does not seem to influence the phenomenon previously described.     

Maximal lactate steady state as a training stimulus

The present study examined the use of the maximal lactate steady state (MLSS) as an exercise training stimulus in moderately trained runners. Fourteen healthy individuals (12 male, 2 female; age 25 +/- 6 years, height 1.76 +/- 0.05 m, body mass 76 +/- 8 kg mean +/- SD) took part in the study. Following determination of the lactate threshold (LT), VO2max, running velocity at MLSS (vMLSS) and a control period of 4 weeks, participants were pair matched and split into two cohorts performing either continuous (CONT: 2 sessions/week at vMLSS) or intermittent treadmill running (INT: 2 sessions/week, 3-min repetitions 0.5 km . h (-1) above and below vMLSS). vMLSS increased in CONT by 8 % from 12.3 +/- 1.5 to 13.4 +/- 1.6 km . h (-1) (p < 0.05) and in INT by 5 % from 12.2 +/- 1.9 km . h (-1) to 12.9 +/- 1.9 km . h (-1) (p < 0.05). Running speed at the LT increased by 7 % in the CONT group (p < 0.05) and by 9 % in the INT group (p < 0.05). VO2max increased by 10 % in the CONT group (p < 0.05) and by 6 % in INT (p < 0.05). Two sessions per week at vMLSS are capable of eliciting improvements in the physiological responses at LT, MLSS, and VO2max in moderately trained runners.     

Effects of an entire season on physical fitness in elite female handball players

PURPOSE: Sixteen elite female handball players were studied to examine the effects of an entire season on anthropometric characteristics, physical fitness, and throwing velocity. METHODS: One-repetition-maximum bench press (1RMBP), jumping explosive strength, power-load relationship of the leg and arm extensor muscles, 5- and 15-m sprint running time, endurance running, and handball throwing velocity were assessed in four periods. Individual volumes and intensities of training and competition were quantified for 11 activities. RESULTS: During the season, significant increases (P < 0.05-0.01) occurred in fat-free mass (1.8 +/- 1.2%), 1RMBP (11 +/- 7.4%), bench press (12-21%) and half-squat (7-13%) muscle power output, vertical jumping height (12 +/- 7.2%), throwing velocity (8 +/- 5.9%), and a significant decrease in percent body fat (9 +/- 8.7%). No changes were observed in sprint and endurance running. Significant correlations (P < 0.05-0.01) were observed between time devoted to games and changes in velocity at submaximal loads during bench press actions, as well as between changes in muscle velocity output of the upper and lower extremities and changes in throwing velocity. Changes in percent body fat or body mass correlated (P < 0.01) positively with changes in maximal strength and muscle power. CONCLUSION: The handball season resulted in significant increases in anthropometric characteristics, physical fitness, and throwing velocity. The correlations observed suggest the importance of including explosive strength exercises of the knee and elbow extensions. Special attention may be needed to be paid to the mode of body fat loss, to increase endurance capacity without interfering in strength gains. Official and training games may be an adequate stimulus for enhancing certain physical fitness characteristics in female elite handball players.     

Sprint vs. interval training in football

The aim of this study was to compare the effects of high-intensity aerobic interval and repeated-sprint ability (RSA) training on aerobic and anaerobic physiological variables in male football players. Forty-two participants were randomly assigned to either the interval training group (ITG, 4 x 4 min running at 90 - 95 % of HRmax; n = 21) or repeated-sprint training group (RSG, 3 x 6 maximal shuttle sprints of 40 m; n = 21). The following outcomes were measured at baseline and after 7 weeks of training: maximum oxygen uptake, respiratory compensation point, football-specific endurance (Yo-Yo Intermittent Recovery Test, YYIRT), 10-m sprint time, jump height and power, and RSA. Significant group x time interaction was found for YYIRT (p = 0.003) with RSG showing greater improvement (from 1917 +/- 439 to 2455 +/- 488 m) than ITG (from 1846 +/- 329 to 2077 +/- 300 m). Similarly, a significant interaction was found in RSA mean time (p = 0.006) with only the RSG group showing an improvement after training (from 7.53 +/- 0.21 to 7.37 +/- 0.17 s). No other group x time interactions were found. Significant pre-post changes were found for absolute and relative maximum oxygen uptake and respiratory compensation point (p < 0.05). These findings suggest that the RSA training protocol used in this study can be an effective training strategy for inducing aerobic and football-specific training adaptations.