To investigate the effect of warm-up on 100-m swimming performance.
Twenty competitive swimmers (with a training frequency of 8.0 ± 1.0 sessions/wk) performed 2 maximal 100-m freestyle trials on separate days, with and without prior warm-up, in a counterbalanced and randomized design. The warm-up distance totaled 1000 m and replicated the swimmers' usual precompetition warm-up strategy. Performance (time), physiological (capillary blood lactate concentrations), psychophysiological (perceived exertion), and biomechanical variables (distance per stroke, stroke frequency, and stroke index) were assessed on both trials.
Performance in the 100-m was fastest in the warm-up condition (67.15 ± 5.60 vs 68.10 ± 5.14 s; P = .01), although 3 swimmers swam faster without warm-up. Critical to this was the 1st 50-m lap (32.10 ± 2.59 vs 32.78 ± 2.33 s; P < .01), where the swimmers presented higher distance per stroke (2.06 ± 0.19 vs. 1.98 ± 0.16 m; P = .04) and swimming efficiency compared with the no-warm-up condition (stroke index 3.46 ± 0.53 vs 3.14 ± 0.44 m2 · c1 · s1; P < .01). Notwithstanding this better stroke-kinematic pattern, blood lactate concentrations and perceived exertion were similar between trials.
These results suggest that swimmers' usual warm-up routines lead to faster 100-m freestyle swimming performance, a factor that appears to be related to better swimming efficiency in the 1st lap of the race. This study highlights the importance of performing swimming drills (for higher distance per stroke) before a maximal 100-m freestyle effort in similar groups of swimmers.
Age-related fitness declines in athletes can be due to both aging and detraining. Very little is known about the physiological and performance decline of professional cyclists after retirement from competition. To gain some insight into the aging and detraining process of elite cyclists, 5-time Tour de France winner and Olympic Champion Miguel Indurain performed a progressive cycle ergometer test to exhaustion 14 years after retirement from professional cycling (age 46 yrs; body mass 92.2 kg). His maximal values were: oxygen uptake 5.29 l.min-1 (57.4 ml.kg-1.min-1), aerobic power output 450 W (4.88 W.kg-1), heart rate 191 bpm, blood lactate 11.2 mM. Values at the individual lactate threshold (ILT): 4.28 l.min-1 (46.4 ml.kg-1.min-1), 329 W (3.57 W.kg-1), 159 bpm, 2.4 mM. Values at the 4 mM onset of blood lactate accumulation (OBLA): 4.68 l.min-1 (50.8 ml.kg-1.min-1), 369 W (4.00 W.kg-1), 170 bpm. Average cycling gross efficiency between 100 and 350 W was 20.1%, with a peak value of 22.3% at 350 W. Delta efficiency was 27.04%. Absolute maximal oxygen uptake and aerobic power output declined by 12.4 and 15.2% per decade, whereas power output at ILT and OBLA declined by 19.8 and 19.2%. Larger declines in maximal and submaximal values relative to body mass (19.4-26.1%) indicate that body composition changed more than aerobic characteristics. Nevertheless, Indurain's absolute maximal and submaximal oxygen uptake and power output values still compare favorably with those exhibited by active professional cyclists.
The collection of retrospective lap times from video footage is a potentially useful research tool to analyse the pacing strategies in any number of competitive events. The aim of this study was to validate a novel method of obtaining running split time data from publically available video footage. Videos of the 1500m men's final from the 2004 & 2008 Olympics, 2005 & 2009 World Championships and 2010 European Championships were obtained from the You Tube website and split times collected from all competitors using frame by frame playback. The typical error of video split times ranged between 0.02s and 0.11s for the four laps when compared to official split times. Video finishing times were also similar to official finishing times, (Typical Error of 0.04s). The method was shown to be highly reliable showing a typical error of 0.02s when the same video was analysed on two occasions separated by 8 months. Video data of track races are widely available however camera angles are not always perpendicular to the start/finish line and some slower athletes may cross the line after the camera has panned away. Nevertheless the typical errors reported here show that, when appropriate camera angles are available, this method is both valid and reliable.
This case study examines the impact of low serum ferritin (sFe) on physiological assessment measures and performance in a young female 1500m runner undertaking approximately 95- 130 km·week-1 training. The study spans 4 race seasons and an Olympic Games. Within this period, 25 venous blood samples were analysed for sFe and haemoglobin (Hb); Running economy, VO2max and lactate threshold were measured on 6 occasions, each separated by 8-10 months. Training was carefully monitored including 65 monitored treadmill training runs (targetting an intensity associated with the onset of blood lactate accumulation) using blood lactate and heart rate. Performances at competitive track events were recorded. All data were compared longitudinally. Mean sFe was 24.5+7.6μg·L-1 (range:10-47) appearing to be in gradual decline with the exception of two data points (37 and 47μg·L-1) following parenteral iron injections prior to championships, where the lowest values tended to occur, coinciding with peak training volumes. 1500m performance improved each season from 4:12.8 in year 1 to 4:03.5 in year 4. VO2max (69.8+2.0ml·kg-1·min-1) and running economy (% of VO2max at a fixed speed of 16km·h-1; max: 87.8%, min: 80.3%) were stable across time and lactate threshold improved (from 14 to 15.5km·hr-1). Evidence of anaemia (Hb<12g·dL-1) was absent. These unique data demonstrate that in one endurance athlete performance can continue to improve despite an apparent iron deficiency. Raising training volume may have caused increased iron utilisation, however, the effect of this on performance is unknown. Iron injections were effective in raising sFe in the short term but did not appear to affect the long term pattern.
To assess the reliability and stability of 400-m swimming and 1500-m track running competitions in order to establish the number of samples needed to obtain a stable pacing profile. Coaches, athletes and researchers can use these methods to ensure sufficient data is collected before training and race strategies are constructed or research conclusions drawn.
Lap times were collected from 5 World and European Championship finals between 2005 and 2011 resulting in the capture of data from 40 swimmers and 55 runners. A cumulative mean for each lap was calculated starting with the most recent data and the number of races needed for this to stabilize to within 1% was reported. Typical Error for each lap was calculated for athletes who had competed in more than 1 final.
International swimmers demonstrated more reproducible performances than runners in three of the four laps of the race (p<0.01). Variance in runners lap times significantly decreased by 1.7-2.7% after lap 1 whereas variance in swimmers lap times tended to increase by 0.1 to 0.5% after lap 1. To establish a stable profile at least 10 400-m swimmers and 44 1500-m runners must be included.
A stable race profile was observed from the analysis of five events for 1500-m running and three events for 400-m swimming. Researchers and athletes can be more certain about the pacing information which is collected from 400-m swimming than 1500-m running races as the swimming data is less variable, despite both events being of similar duration.
This case study observed the training delivered by a 1500-m runner and the physiological and performance change during a 2-y period. A male international 1500-m runner (personal best 3:38.9 min:s, age 26 y, height 1.86 m, body mass 76 kg) completed 6 laboratory tests and 14 monitored training sessions, during 2 training years. Training distribution and volume was ascertained from training diary and spot-check monitoring of heart rate and accelerometry measurements. Testing and training information were discussed with coach and athlete from which training changes were made. In the first training year, low-intensity training was found to be performed above the prescribed level, which was adjusted with training and coach support in y 2 (training zone < 80% of vVO2max, y 1 = 20%; y 2 = 55%). "Tempo" training was also performed at an excessively high intensity (Δ [blood lactate] 5-25 min of tempo run, y 1 = Δ6.7 mM, y 2 = Δ2.5 mM). From y 1 to 2, there was a concomitant increase in the proportion of training in the high-intensity zone of 100 to 130% vVO2max from 7 to 10%. Values for VO2max increased from 72 to 79 mL · kg-1 · min, economy improved from 210 to 206 mL · kg-1 · min, and 1500-m performance time improved from 3:38.9 to 3:32.4 min:s from the beginning of y 1 to the end of y 2. This case shows a modification in training methodology that was coincident with a greater improvement in physiological capability and furtherance in performance improvement.
To compare the physiological responses and maximal aerobic running velocity (MAV) during an incremental intermittent (45-s run/15-s rest) field test (45-15FIT) vs an incremental continuous treadmill test (TR) and to demonstrate that the MAV obtained during 45-15FIT (MAV45-15) was relevant to elicit a high percentage of maximal oxygen uptake (VO2max) during a 30-s/30-s intermittent training session.
Oxygen uptake (VO2), heart rate (HR), and lactate concentration ([La]) were measured in 20 subjects during 2 maximal incremental tests and four 15-min intermittent tests. The time spent above 90% and 95% VO2max (t90% and t95% VO2max, respectively) was determined.
Maximal physiological parameters were similar during the 45-15FIT and TR tests (VO2max 58.6±5.9 mL·kg(-1)·min(-1) for TR vs 58.5±7.0 mL·kg(-1)·min(-1) for 45-15FIT; HRmax 200±8 beats/min for TR vs 201±7 beats/min for 45-15FIT). MAV45-15 was significantly (P<.001) greater than MAVTR (17.7±1.1 vs 15.6±1.4 km/h). t90% and t95% VO2max during the 30-s/30-s performed at MAVTR were significantly (P<.01) lower than during the 30-s/30-s performed at MAV45-15. Similar VO2 during intermittent tests performed at MAV45-15 and at MAVTR can be obtained by reducing the recovery time or using active recovery.
The results suggested that the 45-15FIT is an accurate field test to determine VO2max and that MAV45-15 can be used during high-intensity intermittent training such as 30-s runs interspersed with 30-s rests (30-s/30-s) to elicit a high percentage of VO2max.
This study investigated the decrement in running performance of elite soccer players competing at low altitude and time course for abatement of these decrements.
Twenty elite youth soccer players had their activity profile, in a sea-level (SL) and 2 altitude (Alt, 1600 m, d 4, and d 6) matches, measured with a global positioning system. Measures expressed in meters per minute of match time were total distance, low- and high-velocity running (LoVR, 0.01-4.16 m/s; HiVR, 4.17-10.0 m/s), and frequency of maximal accelerations (>2.78 m/s2). The peak and subsequent stanza for each measure were identified and a transient fatigue index calculated. Mean heart rate (HR) during the final minute of a submaximal running task (5 min, 11 km/h) was recorded at SL and for 10 d at Alt. Differences were determined between SL and Alt using percentage change and effect-size (ES) statistic with 90% confidence intervals.
Mean HR almost certainly increased on d 1 (5.4%, ES 1.01 ± 0.35) and remained probably elevated on both d 2 (ES 0.42 ± 0.31) and d3 (ES 0.30 ± 0.25), returning to baseline at d 5. Total distance was almost certainly lower than SL (ES -0.76 ± 0.37) at d 4 and remained probably reduced on d 6 (ES -0.42 ± 0.36). HiVR probably decreased at d 4 vs SL (-0.47 ± 0.59), with no clear effect of altitude at d 6 (-0.08 ± 0.41). Transient fatigue in matches was evident at SL and Alt, with a possibly greater decrement at Alt.
Despite some physiological adaptation, match running performance of youth soccer players is compromised for at least 6 d at low altitude.
To determine the incidence of exercise-associated hyponatremia (EAH), the associated biochemical measurements and risk factors for EAH, and whether there is an association between postrace blood sodium concentration ([Na+]) and changes in body mass among participants in the 2009 Western States Endurance Run, a 161-km mountain trail run.
Change in body mass, postrace [Na+], and blood creatine phosphokinase (CPK) concentration, and selected runner characteristics were evaluated among consenting competitors.
Of the 47 study participants, 14 (30%) had EAH as defined by a postrace [Na+] <135 mmol/L. Postrace [Na+] and percent change in body mass were directly related (r = .30, P = .044), and 50% of those with EAH had body mass losses of 3-6%. EAH was unrelated to age, sex, finish time, or use of nonsteroidal anti-inflammatory drugs during the run, but those with EAH had completed a smaller (P = .03) number of 161-km ultramarathons. The relationship of CPK levels to postrace [Na+] did not reach statistical significance (r = -.25, P = .097).
EAH was common (30%) among finishers of this 161-km ultramarathon and it was not unusual for those with EAH to be dehydrated. As such, changes in body mass should not be relied upon in the assessment for EAH during 161-km ultramarathons.
To determine if beliefs about physiology and rehydration affect ultramarathon runners' hydration behaviors or if these beliefs increase the risk for exercise-associated hyponatremia (EAH).
Participants of the 2011 161-km Western States Endurance Run completed a prerace questionnaire, prerace and postrace body-mass measurements, and postrace assessment of serum sodium ([Na⁺]).
Of 310 finishers, 309 (99.7%) completed the prerace questionnaire and 207 (67%) underwent postrace blood studies. Twelve (5.8%) finishers had asymptomatic EAH ([Na⁺] range 131-134 mmol/L). The most common hydration plan (43.1%) was drinking according to schedule, and these runners did so to replace fluid lost when sweating (100%) and to avoid dehydration (81.2%). Prerace drinking plan was not associated with postrace [Na⁺] or the development of postrace hyponatremia. There also were no group differences between those with and those without EAH for any other variables including planned energy intake or knowledge of fluid balance. Runners not planning to drink to thirst trended toward more influence from advertisements (P = .056) and were significantly more influenced by scientific organizations (P = .043) than runners with other drinking plans. Finally, runners who believe that EAH is caused by excessive drinking adopted a lower-volume drinking plan (P = .005), while runners who believe that EAH is caused by sodium loss via sweating reported more common use of sodium supplementation during the race (P = .017).
Beliefs regarding the causes of EAH alter race behaviors including drinking plan and sodium supplementation but do not appear to affect the likelihood of developing EAH during a 161-km ultramarathon.
Despite increased 161-km ultramarathon participation in recent years, little is known about those who pursue such an activity. This study surveyed entrants in two of the largest 161-km trail ultramarathon runs in North America to explore demographic characteristics and issues that affected race performance.
All entries of the 2009 Western States Endurance Run and the Vermont 100 Endurance Race were invited to complete a postrace questionnaire.
There were 500 respondents among the 701 race entries (71.3% response). Finish time was found to have a significant (P ≤ .01) negative association with training volume and was generally directly associated with body mass index. Among nonfinishers, the primary reason for dropping out was nausea and/or vomiting (23.0%). Finishers compared with nonfinishers were more likely (P ≤ .02) to report blisters (40.1% vs 17.3%), muscle pain (36.5% vs 20.1%), and exhaustion (23.1% vs 13.7%) as adversely affecting race performance, but nausea and/or vomiting was similar between groups (36.8% vs 39.6%). Nausea and/or vomiting was no more common among those using nonsteroidal anti-inflammatory drugs (NSAIDs), those participating in the event with higher ambient temperatures, those with a lower training volume, or those with less experience at finishing 161-km races. Overall use of NSAIDs was high, and greater (P = .006) among finishers (60.5%) than nonfinishers (46.4%).
From this study, we conclude that primary performance-limiting issues in 161-km ultramarathons include nausea and/or vomiting, blisters, and muscle pain, and there is a disturbingly high use of NSAIDs in these events.
Even pacing has been recommended for optimal performances in running distances up to 100 km. Trail ultramarathons traverse varied terrain, which does not allow for even pacing.
This study examined differences in how runners of various abilities paced their efforts in the Western States Endurance Run (WSER), a 161 km trail ultramarathon in North America, under hot vs cooler temperatures.
Temperatures in 2006 (hot) and 2007 (cooler) ranged from 7-38°C and 2-30°C, respectively. Arrival times at 13 checkpoints were recorded for 50 runners who finished the race in both years. After stratification into three groups based on finish time in 2007 (<22, 22-24, 24-30 h), paired t tests were used to compare the difference in pace across checkpoints between the years within each group. The χ2 test was used to compare differences between the groups on the number of segments run slower in the hot vs cooler years.
For all groups, mean pace across the entire 161 km race was slower in 2006 than in 2007 (9:23 ± 1:13 min/km vs 8:42 ± 1:15 min/km, P < .001) and the pace was slower from the start of the race when temperatures were still relatively cool. Overall, the <22 h cohort ran slower in 2006 than 2007 over 12 of the 14 segments examined, the 22-24 h cohort was slower across 10 of the segments, and the >24 h cohort was slower across only 6 of the segments χ(2)2 = 6.00, P = .050). Comparable pacing between the 2 y corresponded with onset of nighttime and cooling temperatures.
Extreme heat impairs all runners' ability to perform in 161 km ultramarathons, but faster runners are at a greater disadvantage compared with slower competitors because they complete a greater proportion of the race in the hotter conditions.
This work examines pacing among the most successful runners in the 161-km Western States Endurance Run (WSER) to determine if variations in segmental speed relate to performance, ambient temperature and calendar year.
Segmental speed and coefficient of variation (CV) in speed were analyzed for ten race segments of 24 races from 1985 through 2013.
Segmental speeds did not differ between the eventual winners and lead runners, and only differed between the first and second finishers in the second half of the race. Mean CV in speed was lower (p<0.01) for the winners (12%) compared with the other top-five finishers (14-15%). CV in speed was related (r=0.80, p=0.006) to finish time for the fastest ten finish times at the WSER. Multiple linear regression analysis revealed mean CV in speed for the top-five runners to be related to maximum ambient temperature (coefficient=0.14, p<0.05) and calendar year (coefficient=-0.086, p=0.034).
Mountain trail running is characterized by wide variations in speed, but the fastest times are achieved when speed fluctuations are limited. This is generally accomplished by the winners remaining relatively close behind the lead runners before taking the lead in the middle half of the race, and then avoiding slowing as much as the other top runners in the latter race stages. Variations in speed increase with high ambient temperatures, and the small decrease in segmental speed variability among top runners across the nearly 30 years of this study suggests that the best runners have improved at pacing this race.
To provide the time-motion and physiological profile of regular training sessions (TS) performed during the competitive season by under-15 (U15), under-17 (U17), and under-19 (U19) elite-level Portuguese soccer players.
One hundred fifty-one elite players of U15 (age 14.0 ± 0.2 y, n = 56), U17 (age 15.8 ± 0.4 y, n = 66), and U19 (age 17.8 ± 0.6 y, n = 29) participated in the study during a 9-wk period. Time-motion and body-impact data were collected using GPS technology (15 Hz) across 38 randomly selected TS that resulted in a total of 612 samples. In addition, heart rate (HR) was continuously monitored (1 Hz) in the selected TS.
The total distances covered (m) were higher in U17 (4648.3 ± 831.9), followed by U19 (4212.5 ± 935.4) and U15 (3964.5 ± 725.4) players (F = 45.84, P < .001). Total body impacts and relative impacts were lower in U15 (total: 490.8 ± 309.5, F = 7.3, P < .01), but no differences were identified between U17 (total: 584.0 ± 363.5) and U19 (total: 613.1 ± 329.4). U19 players had less high- and very-high-intensity activity (above 16 km/h; F = 11.8, P < .001) and moderate-intensity activity (10.0-15.9 km/h; F = 15.07, P < .001). HR values showed significant effects of zone (F = 575.7, P < .001) and interaction with age group (F = 9.7, P < .001), with pairwise differences between all zones (zone 1, <75%; zone 2, 75-84.9%; zone 3, 85-89.9%; zone 4, ≥90%). All players spent most of their time below 75% HRmax (U15, ~50%; U17, ~42%; U19, ~50%).
Results showed high variability between TS, refraining from identifying meaningful trends when measuring performance, although different demands were identified according to age group. The U15 TS were less physiologically demanding, probably because of increased focus on small-sided games to develop basic tactical principles and technical skills. The focus on game-like situations imposed higher external and internal workloads on U17 and U19 players.
The understanding of the gap between Under 18 y (U18) and senior-level competition and the evolution of this gap in Australian Football lack a strong evidence base. Despite the multimillion dollars invested in recruitment, scientific research on successful transition is limited. No studies have compared individual players' movement rate, game statistics and ball speed in U18 and senior competition of the Australian Football League across time. This project compared differences in player movement and ball speed between matches from senior AFL competitive matches and U18 players in the 2003 and 2009 seasons.
TrakPerformance Software and Global Positioning System (GPS) technology were used to analyze the movement of players, ball speed and game statistics. ANOVA compared the two levels of competition over time.
Observed interactions for distance traveled per minute of play (P = .009), number of sprints per minute of play (P < .001), time spent at sprint speed in the game (P < .001), time on field (P < .001), and ball speed (P < .001) were found. Subsequent analysis identified increases in movement patterns in senior AFL competition in 2009 compared with the same level of competition in 2003 and U18 players in 2003 and 2009.
Senior AFL players in 2009 were moving further, sprinting relatively more frequently, playing less time and playing at game speeds significantly greater than the same senior competition in 2003 as well as compared with both cohorts of U18 players.
The sex difference in ultraendurance performance has been investigated in swimmers, runners, and triathletes but not in cyclists. The purpose of this study was to examine the sex difference in the longest ultra-cycling race in the world, the Race Across America (RAAM).
Cycling speed of female and male finishers in the RAAM between 1982 and 2012 was compared.
A total of 452 athletes including 404 men (89.4%) and 48 women (10.6%) finished. Mean cycling speed was 19.4 ± 2.0 km/h for men and 17.5 ± 2.0 km/h for women. Men were riding 1.9 ± 2.0 km/h (10.9%) faster than women. The fastest cycling speed ever was 24.77 km/h for men and 21.27 km/h for women, with a sex difference of 14.2%. Between 1982 and 2012, cycling speed was 22.7 ± 1.1 km/h for the annual fastest men and 18.4 ± 1.6 km/h for the annual fastest women, with an unchanged sex difference of 19.4% ± 7.3% (P > .05). For the annual top 3 men, cycling speed was 21.8 ± 0.9 km/h with no change across years (P > .05). The annual top 3 women achieved a cycling speed of 16.6 ± 1.0 km/h with no change over time (P > .05). The sex difference of 24.6% ± 3.0% showed no change across years (P > .05).
In the last 30 y, men crossed America faster than women, and it seems unlikely that women will overtop men in the near future in the RAAM. However, the sex difference was only 14-15% among top competitors. Future studies need to analyze anthropometric, psychological, and physiological characteristics of successful female and male ultracyclists.
Recent studies suggested that women and men's ultra-swim performances may be similar for distances of ~35 km. The present study investigated both the gender difference and the age of peak ultra-swim performance between 1983 and 2013 at the 46-km 'Manhattan Island Marathon Swim' with water temperatures <20°C.
Changes in race times and gender difference in 551 male and 237 female finishers were investigated using linear, non-linear, and hierarchical multi-level regression analyses.
The top ten race times ever were significantly (P<0.0001) lower for women (371±11 min) than for men (424±9 min). Race times of the annual fastest and annual three fastest women and men did not differ between genders and remained stable across years. The age of the annual three fastest swimmer increased from 28±4 years (1983) to 38±6 years (2013) (r2=0.06, P=0.03) in women and from 23±4 years (1984) to 42±8 years (2013) (r2=0.19, P<0.0001) in men.
The best women were ~12-14% faster than the best men in a 46-km open-water ultra-distance race with temperatures <20°C. The maturity of ultra-distance swimmers has changed during the last decades with the fastest swimmers becoming older across the years.
The purpose of this investigation was to quantify maximal aerobic power (VO2max) in soccer as a function of performance level, position, age, and time of season. In addition, the authors examined the evolution of VO2max among professional players over a 23-y period.
1545 male soccer players (22 ± 4 y, 76 ± 8 kg, 181 ± 6 cm) were tested for VO2max at the Norwegian Olympic Training Center between 1989 and 2012.
No differences in VO2max were observed among national-team players, 1st- and 2nd-division players, and juniors. Midfielders had higher VO2max than defenders, forwards, and goalkeepers (P < .05). Players <18 y of age had ~3% higher VO2max than 23- to 26-y-old players (P = .016). The players had 1.6% and 2.1% lower VO2max during off-season than preseason (P = .046) and in season (P = .021), respectively. Relative to body mass, VO2max among the professional players in this study has not improved over time. Professional players tested during 2006-2012 actually had 3.2% lower VO2max than those tested from 2000 to 2006 (P = .001).
This study provides effect-magnitude estimates for the influence of performance level, player position, age, and season time on VO2max in men's elite soccer. The findings from a robust data set indicate that VO2max values ~62-64 mL · kg-1 · min-1 fulfill the demands for aerobic capacity in men's professional soccer and that VO2max is not a clearly distinguishing variable separating players of different standards.
To quantify VO2max among female competitive soccer players as a function of performance level, field position, and age. In addition, the evolution of VO2max among world-class players over an 18-y period was quantified.
Female players (N = 199, 22 ± 4 y, 63 ± 6 kg, height 169 ± 6 cm), including an Olympic winning squad, were tested for VO2max at the Norwegian Olympic Training Center between 1989 and 2007.
National-team players had 5% higher VO2max than 1st-division players (P = .042, d = 0.4), 13% higher than 2nd-division players (P < .001, d = 1.2), and 9% higher than junior players (P = .005, d = 1.0). Midfielders had 8% higher VO2max than goalkeepers (P = .048, d = 1.1). No significant differences were observed across outfield players or different age categories. There was a trend toward lower relative VO2max across time epochs.
This study demonstrated that VO2max varies across playing-standard level in women's soccer. No significant differences in VO2max were observed across outfield positions and age categories. Over time, there has been a slight negative development in VO2max among elite Norwegian soccer players.
The Paralympic Games have undergone many changes since its inception in 1960, one being the advances made in running specific prosthesis (RSP) for track athletes with lower limb amputations.
The purpose of this study was to investigate the sprinting performance changes in athletes with lower limb amputations since 1992 to assess whether the influence of developments in RSP technology is evident.
The results of the Olympic and Paralympic Games ranging between 1992 and 2012 for the 100m and 200m were collected and performance trends, percentage change in performance and competition density (CD) were calculated.
The results indicate that the greatest performance increases were seen in athletes with lower limb amputations (T42 = 26%, T44 = 14%). These performance improvements were greater than for Olympic athletes (<3%), as well as Paralympic athletes from other selected classes (<10%). The T42 and T44 classes also showed the lowest CD values.
These results suggest that although there is an overall trend for improved Paralympic sprint performances, RSP technology has played a noteworthy role in the progression of performances of athletes with amputations. It is also hypothesized that the difference in the performance improvements between the T42 and T44 classes is due to the level of disability and therefore the extent to which technology is required to enable locomotion.
It is evident that RSP technology has played a significant role in the progression of performances in athletes with lower limb amputations.
To compare sprint and countermovement-jump (CMJ) performance among competitive soccer players as a function of performance level, field position, and age. In addition, the authors wanted to quantify the evolution of these physical characteristics among professional players over a 15-y period.
939 athletes (22.1 ± 4.3 y), including national-team players, tested 40-m sprint with electronic timing and CMJ on a force platform at the Norwegian Olympic Training Center between 1995 and 2010.
National-team and 1st-division players were faster (P < .05) than 2nd-division (1.0-1.4%), 3rd- to 5th-division (3.0-3.8%), junior national-team (1.7-2.2%), and junior players (2.8-3.7%). Forwards were faster than defenders (1.4%), midfielders (2.5%), and goalkeepers (3.2%) over 0-20 m (P < .001). Midfielders jumped ~2.0 cm lower than the other playing positions (P < .05). Sprinting velocity peaked in the age range 20-28 y and declined significantly thereafter (P < .05). Players from 2006-2010 had 1-2% faster 0-20 m and peak velocity than players from the 1995-1999 and 2000-2005 epochs, whereas no differences in CMJ performance were observed.
This study provides effect-magnitude estimates for the influence of performance level, position, and age on sprint and CMJ performance in soccer. While CMJ performance has remained stable over the time, there has been a small but positive development in sprinting velocity among professional players.
The purpose of this investigation was to compare sprint and countermovement-jump (CMJ) performance among female competitive soccer players as a function of performance level, field position, and age. In addition, the authors wanted to quantify the evolution of these physical characteristics among elite players over a 15-y period.
194 female elite players (22± 4.1 y, 63 ± 5.6 kg), including an Olympic winning squad, tested 40-m sprint with electronic timing and CMJ on a force platform at the Norwegian Olympic training center from 1995 to 2010.
Moderate to large velocity differences across performance levels and positions were observed. National-team players were 2% faster than 1st-division players (P = .027, d = 0.5) and 5% faster than 2nd-division players (P < .001, d = 1.3) over 0-20 m. National-team players jumped 8-9% higher than 1st-division players (P = .001, d = 0.6) and junior elite players (P = .023, d = 0.5). Forwards were 3-4% faster than midfielders (P < .001, d = 0.8) and goalkeepers (P = .003, d = 0.9) over 0-20 m. No differences in velocity or CMJ height were observed among the age categories. Players from 2006-2010 were 2% faster (P < .05, d = 0.6) than players from 1995-1999 over 20 m, whereas no differences in 20- to 40-m velocity or CMJ performance were observed.
This study provides effect-magnitude estimates for the influence of performance level, age, and player position on sprint and CMJ performance in female soccer players. While 20- to 40-m velocity and CMJ performance have remained stable over the time, there has been a moderate but positive development in 0- to 20-m velocity among elite performers.
Thompson and Cooper1 observed that improvements in the swimming speed at 2-mM and 6-mM lactate concentration coincided with improvements in competitive breaststroke performances, whereas Pyne et al concluded that changes in swimming speed at lactate threshold were not directly associated with competition performances in a mixed-stroke group of 12 elite swimmers. This case study presents data from eleven (7 x 200 m) step tests over a 3-year period for a world-class 200-m male breaststroke swimmer. Personal-best race times were reduced by 9.5 seconds over this period. For this individual, step-test data provided valuable information with regard to the swimmer's readiness for performance, health and training status, and nutritional habits.
Optimal pacing strategy was determined for breaking the world speed record on a human-powered vehicle (HPV) using an energy-flow model in which the rider's physical capacities, the vehicle's properties, and the environmental conditions were included. Power data from world-record attempts were compared with data from the model, and race protocols were adjusted to the results from the model. HPV performance can be improved by using an energy-flow model for optimizing race strategy. A biphased in-run followed by a sprint gave best results.
Optimal pacing strategy was determined for breaking the world speed record on an HPV using an energy flow model in which the rider's physical capacities, the vehicle's properties and the environmental conditions were included. Power data from world record attempts were compared with data from the model and race protocols were adjusted to the results from the model. HPV performance can be improved by using an energy flow model for optimizing race strategy. A bi-phased in-run followed by a sprint gave best results.
Warm-up before athletic competition might enhance performance by affecting various physiological parameters. There are few quantitative data available on physiological responses to the warm-up, and the data that have been reported are inconclusive. Similarly, it has been suggested that varying the recovery period after a standardized warm-up might affect subsequent performance.
To determine the effects of varying post-warm-up recovery time on a subsequent 200-m swimming time trial.
Ten national-caliber swimmers (5 male, 5 female) each swam a 1500-m warm-up and performed a 200-m time trial of their specialty stroke after either 10 or 45 min of passive recovery. Subjects completed 1 time trial in each condition separated by 1 wk in a counterbalanced order. Blood lactate and heart rate were measured immediately after warm-up and 3 min before, immediately after, and 3 min after the time trial. Rating of perceived exertion was measured immediately after the warm-up and time trial.
Time-trial performance was significantly improved after 10 min as opposed to 45 min recovery (136.80 +/- 20.38 s vs 138.69 +/- 20.32 s, P < .05). There were no significant differences between conditions for heart rate and blood lactate after the warm-up. Pre-time-trial heart rate, however, was higher in the 10-min than in the 45-min rest condition (109 +/- 14 beats/min vs 94 +/- 21 beats/min, P < .05). Conclusions: A post-warm-up recovery time of 10 min rather than 45 min is more beneficial to 200-m swimming time-trial performance.
To investigate the effect of ingesting a caffeinated carbohydrate gel (CC) 10 minutes prior on 2000-m rowing performance compared with a carbohydrate-only placebo gel (CP).
A counterbalanced, single-blind, crossover study design was employed (N=13). All participants completed 1 familiarization trial followed by 2 experimental rowing time trials. The experimental trials were performed 10 min after ingesting CP (21.6 g of carbohydrate, 0 mg caffeine) or CC (21.6 g carbohydrate, 100 mg caffeine), and heart rate (HR), oxygen consumption (VO2), carbon dioxide production, minute ventilation (VE), respiratory-exchange ratio (RER), rating of perceived exertion (RPE), gastrointestinal discomfort (GI), and thirst perception (Thirst) were recorded every 200 m. Blood lactate [La-] was recorded immediately before and after exercise.
A pairedsamples t test identified a significant improvement in 2000-m performance of 5.2±3.9 s (1.1%±1.7%; P=.034). Two-way repeated-measures ANOVA revealed no significant treatment effect for HR (177±8 vs 177±9 beats/min, P=.817), VO2 (46.1±6.5 vs 46.6±6.2 mL·kg(-1)·min(-1), P=.590), VE (121.8±14.7 vs 124.8±15.7 L/min, P=.490), RPE, GI, or Thirst for CP and CC, respectively. Paired-samples t tests revealed no treatment effect for postexercise [La-] between CP and CC (11.72±2.69 vs 12.26±3.13 mmol/L, P=.534).
A relatively low dose of caffeine (1.3±0.1 mg/kg body mass) in an isotonic carbohydrate gel ingested only 10 min before performance improved 2000-m rowing time by 5.2±7.8 s (1.1%±1.7%).
The aim of this study was to determine the effect and reliability of acute and chronic sodium bicarbonate ingestion for 2000-m rowing ergometer performance (watts) and blood bicarbonate concentration [HCO3-].
In a crossover study, 7 well-trained rowers performed paired 2000-m rowing ergometer trials under 3 double-blinded conditions: (1) 0.3 grams per kilogram of body mass (g/kg BM) acute bicarbonate; (2) 0.5 g/kg BM daily chronic bicarbonate for 3 d; and (3) calcium carbonate placebo, in semi-counterbalanced order. For 2000-m performance and [HCO3-], we examined differences in effects between conditions via pairwise comparisons, with differences interpreted in relation to the likelihood of exceeding smallest worthwhile change thresholds for each variable. We also calculated the within-subject variation (percent typical error).
There were only trivial differences in 2000-m performance between placebo (277 ± 60 W), acute bicarbonate (280 ± 65 W) and chronic bicarbonate (282 ± 65 W); however, [HCO3-] was substantially greater after acute bicarbonate, than with chronic loading and placebo. Typical error for 2000-m mean power was 2.1% (90% confidence interval 1.4 to 4.0%) for acute bicarbonate, 3.6% (2.5 to 7.0%) for chronic bicarbonate, and 1.6% (1.1 to 3.0%) for placebo. Postsupplementation [HCO3-] typical error was 7.3% (5.0 to 14.5%) for acute bicarbonate, 2.9% (2.0 to 5.7%) for chronic bicarbonate and 6.0% (1.4 to 11.9%) for placebo.
Performance in 2000-m rowing ergometer trials may not substantially improve after acute or chronic bicarbonate loading. However, performances will be reliable with both acute and chronic bicarbonate loading protocols.
Beetroot juice is a naturally rich source of inorganic nitrate (NO3-), a compound hypothesized to enhance endurance performance by improving exercise efficiency.
This study investigated the effect of different doses of beetroot juice on 2,000 m ergometer rowing performance in highly trained athletes.
Ten highly trained male rowers volunteered to participate in a placebo controlled, double blinded cross-over study. Two hours before undertaking a 2,000 m rowing ergometer test, subjects consumed beetroot juice containing 0 mmol (PLACEBO), 4.2 mmol (SINGLE) or 8.4 mmol (DOUBLE) NO3-. Blood samples were taken before supplement ingestion and immediately before the rowing test for analysis of plasma [NO3-] and [nitrite (NO2-)].
The SINGLE dose demonstrated a trivial effect on time to complete 2,000 m compared to PLACEBO (mean difference: 0.2 ± 2.5 s). A possibly beneficial effect was found with DOUBLE compared to SINGLE (mean difference: -1.8 ± 2.1 s) and PLACEBO (-1.6 ± 1.6 s) respectively. Plasma [NO2-] and [NO3-] demonstrated a dose-response effect, with greater amounts of ingested nitrate leading to substantially higher concentrations (DOUBLE > SINGLE > PLACEBO). There was a moderate but insignificant correlation (r=-0.593, p=0.055) between change in plasma [NO2-] and performance time.
When compared with nitrate-depleted beetroot juice, a high (8.4 mmol NO3-) but not moderate (4.2 mmol NO3-) dose of NO3- in beetroot juice, consumed 2 h before exercise, may improve 2,000m rowing performance in highly trained athletes.
The ability to buffer H+ could be vital to exercise performance, as high concentrations of H+ contribute to the development of fatigue.
The authors examined the effect of sodium bicarbonate (SB) supplementation on 2000-m rowing-ergometer performance.
Twenty male rowers (age 23 ± 4 y, height 1.85 ± 0.08 m, mass 82.5 ± 8.9 kg, 2000-m personal-best time 409 ± 16 s) completed two 2000-m rowing-ergometer time trials, separated by 48 h. Participants were supplemented before exercise with 0.3 g/kg body mass of SB or a placebo (maltodextrin; PLA). The trials were conducted using a double-blinded, randomized, counterbalanced crossover study design. Time to complete the 2000-m and time taken for each 500-m split were recorded. Blood lactate, bicarbonate, pH, and base excess were determined preexercise, immediately postexercise, and 5 min postexercise. Performance data were analyzed using paired t tests, as well as magnitude-based inferences; hematological data were analyzed using a repeated-measures ANOVA.
Using paired t tests, there was no benefit of SB over PLA (P = .095). However, using magnitude-based inferences there was a likely beneficial effect of SB compared with PLA (PLA 412.0 ± 15.1 s, SB 410.7 ± 14.9 s). Furthermore, SB was 0.5 ± 1.2 s faster than PLA in the third 500 m (P = .035; possibly beneficial) and 1.1 ± 1.7 s faster in the fourth 500 m (P = .004; very likely beneficial). All hematological data were different between SB and PLA and were different from preexercise to postexercise.
SB supplementation is likely to be beneficial to the performance of those competing in 2000-m rowing events, particularly in the second half of the event.
This study examined parameters derived from both an incremental step-wise and a ramp-wise graded rowing exercise test in relation to rowing performance.
Discontinuous step-wise incremental rowing to exhaustion established lactate threshold (LT), maximum oxygen consumption (VO(2maxSTEP)), and power associated with VO(2max) (W VO(2max)). A further continuous ramp-wise test was undertaken to derive ventilatory threshold (VT), maximum oxygen consumption (VO(2maxRAMP)), and maximum minute power (MMW). Results were compared with maximal 2000-m ergometer time-trial power.
The strongest correlation with 2000-m power was observed for MMW (r = .98, P < .001), followed by W VO(2max) (r = .96; P < .001). The difference between MMW and W VO(2max) compared with the mean of MMW/W VO(2max) showed a widening bias with a greater difference coincident with greater power. However, this bias was reduced when expressed as a ratio term and when a baseline VO₂ was accounted for. There were no differences (P = .85) between measures of VO(2maxSTEP) and VO(2maxRAMP); rather, the measures showed strong association (r = .97, P < .001, limits of agreement = -0.43 to 0.33 L/min). The power at LT and VT did not differ (P = .6), and a significant association was observed (r = .73, P = .001, limits of agreement = -54.3 to 20.2 W, SEE = 26.1).
This study indicates that MMW demonstrates a strong association with ergometer rowing performance and thus may have potential as an influential monitoring tool for rowing athletes.
This study investigated the pacing strategy adopted and the consistency of performance and related physiological parameters across three 2000-m rowing-ergometer tests.
Fourteen male well-trained rowers took part in the study. Each participant performed three 2000-m rowing-ergometer tests interspersed by 3-7 d. Throughout the trials, respiratory exchange and heart rate were recorded and power output and stroke rate were analyzed over each 500 m of the test. At the completion of the trial, assessments of blood lactate and rating of perceived exertion were measured.
Ergometer performance was unchanged across the 3 trials; however, pacing strategy changed from trial 1, which featured a higher starting power output and more progressive decrease in power, to trials 2 and 3, which were characterized by a more conservative start and an end spurt with increased power output during the final 500 m. Mean typical error (TE; %) across the three 2000-m trials was 2.4%, and variability was low to moderate for all assessed physiological variables (TE range = 1.4-5.1%) with the exception of peak lactate (TE = 11.5%).
Performance and physiological responses during 2000-m rowing ergometry were found to be consistent over 3 trials. The variations observed in pacing strategy between trial 1 and trials 2 and 3 suggest that a habituation trial is required before an intervention study and that participants move from a positive to a reverse-J-shaped strategy, which may partly explain conflicting reports in the pacing strategy exhibited during 2000-m rowing-ergometer trials.
To describe the development of anthropometric and physical characteristics of young Swiss alpine skiers between 2004 and 2011; to compare them between age and performance-level groups; and to identify age- and sex-dependent reference values for the tests performed.
The Swiss-Ski Power Test includes anthropometric measures and physical tests for coordination and speed, strength, anaerobic capacity and endurance. We analysed the results of 8176 tests performed by 1579 male and 1109 female alpine skiers between 2004 and 2011. Subjects ranged between regional and national level of performance and were grouped according to their competition age groups (U12: 11-years old; U14: 12 to 13-years old; U16: 14 to 15-years old; U18: 16 to 17-years old; U21: 18 to 20 years old) and performance level.
A progressive increase in anthropometric measures and improvements in tests results with increasing age were found. For all tests, male athletes had better results than female athletes. We observed minor differences in anthropometric characteristics between 2004 and 2011 (mostly <5%), while results of physical and coordinative tests showed significant improvements (up to more than 50% enhancement) or stability over the years. Differences between higher- and lower-level athletes were more pronounced in tests for lower-limb strength and anaerobic capacity.
The profile of young Swiss alpine skiers presented highlights the improvements in different physical aspects along the maturation process and chronologically over a period of 7 years. Furthermore, reference values are provided for comparisons with alpine skiers or athletes from other sports.
To identify tactical factors associated with progression from preliminary rounds in middle-distance running events at an international championship.
Results from the 2012 Olympic Games were used to access final and intermediate positions, finishing times, and season-best (SB) times for competitors in men's and women's 800-m and 1500-m events (fifteen 800-m races and ten 1500-m races). Finishing times were calculated as %SB, and Pearson product-moment correlations were used to assess relationships between intermediate and finishing positions. Probability (P) of qualification to the next round was calculated for athletes in each available intermediate position.
There were no significant differences in finishing times relative to SB between qualifiers and nonqualifiers. In the 800-m, correlation coefficients between intermediate and final positions were r = .61 and r = .84 at 400 m and 600 m, respectively, whereas in the 1500-m, correlations were r = .35, r = .43, r = .55, and r = .71 at 400 m, 800 m, 1000 m, and 1200 m, respectively. In both events, probability of qualification decreased with position at all intermediate distances. At all points, those already in qualifying positions were more likely to qualify for the next round.
The data demonstrate that tactical positioning at intermediate points in qualifying rounds of middle-distance races is a strong determinant of qualification. In 800-m races it is important to be in a qualifying position by 400 m. In the 1500-m event, although more changes in position are apparent, position at intermediate distances is still strongly related to successful qualification.
The planning and organization of athletic training have historically been much discussed and debated in the coaching and sports science literature. Various influential periodization theorists have devised, promoted, and substantiated particular training-planning models based on interpretation of the scientific evidence and individual beliefs and experiences. Superficially, these proposed planning models appear to differ substantially. However, at a deeper level, it can be suggested that such models share a deep-rooted cultural heritage underpinned by a common set of historically pervasive planning beliefs and assumptions. A concern with certain of these formative assumptions is that, although no longer scientifically justifiable, their shaping influence remains deeply embedded. In recent years substantial evidence has emerged demonstrating that training responses vary extensively, depending upon multiple underlying factors. Such findings challenge the appropriateness of applying generic methodologies, founded in overly simplistic rule-based decision making, to the planning problems posed by inherently complex biological systems. The purpose of this review is not to suggest a whole-scale rejection of periodization theories but to promote a refined awareness of their various strengths and weaknesses. Eminent periodization theorists-and their variously proposed periodization models-have contributed substantially to the evolution of training-planning practice. However, there is a logical line of reasoning suggesting an urgent need for periodization theories to be realigned with contemporary elite practice and modern scientific conceptual models. In concluding, it is recommended that increased emphasis be placed on the design and implementation of sensitive and responsive training systems that facilitate the guided emergence of customized context-specific training-planning solutions.
the aim of this study was to investigate physiological performance determinants of the partial laps and overall 22km handbiking (HB) time trial in athletes with high paraplegia.
seven male HB athletes with spinal cord injury (SCI) (lesion levels: thoracic 2 - thoracic 8) performed a laboratory maximal incremental test under cardiorespiratory-mechanical monitoring including respiratory exchange ratio (RER), oxygen uptake (VO2) and mechanical power output (PO). Individual first and second ventilatory thresholds (VO2VT1 and VO2VT2), VO2peak and POpeak were posteriorly identified. Athletes also performed a simulated HB time trial along a 4-lap bike circuit under cardiorespiratory measurement. Overall metabolic cost (C) and %VO2peak (ratio of VO2 to VO2peak) were calculated from race data. Race performance was defined as mean race velocity (v).
athletes completed the 22km HB time trial in 45±6 min, at 29.9±3.6 km/h, with %VO2peak=0.86±0.10 and RER=1.07±0.17. VO2peak (r=0.89, p=0.01), POpeak (r=0.85, p=0.02), VO2VT1 (r=0.96, p=0.001), VO2VT2 (r=0.92, p=0.003) and C (2nd lap, r=0.78; 3rd lap, r=0.80; and 4th lap, r=0.80) were significantly (p<0.05) positively correlated with race performance. Within-subjects correlation coefficient revealed a large and significant (r=0.68, p<0.001) relationship between %VO2peak and v.
VO2peak, POpeak, ventilatory thresholds, %VO2peak and C appeared to be important physiological performance determinants of HB time trial.
The purpose of the study was to determine the reliability of yo-yo intermittent recovery test (yo-yo) scores and their degree of association with a 20-m shuttle run (20MSR) and VO(2max) values.
Subjects were elite (Australian Football League [AFL], n = 23), state-level (hockey, n = 15, and cricket, n = 27), and recreational team-sport players (n = 33). All performed a 20MSR and the yo-yo at either level 1 (recreational and state level) or level 2 (AFL). A recreational subgroup (n = 19) also performed a treadmill VO(2max) test.
Test-retest results found the yo-yo (levels 1 and 2) to be reliable (ICC = .86 to .95). The 20MSR and yo-yo level 1 scores correlated (P < .01) in the recreational (r = .81 to .83) and state-level groups (r = .84 to .86), and 20MSR and yo-yo level 2 scores, in the elite (r = .86) and recreational groups (r = .55 to .57). The VO(2max) and yo-yo level 1 scores in the recreational group correlated (P < .01, r = .87), but no association was found with yo-yo level 2 (r = .40 to .43, nonsignificant).
We conclude that level 1 (recreational and state level) and level 2 (elite) yo-yo scores were both strongly associated with 20MSR scores and VO(2max) (level 1: recreational subjects only). The yo-yo appears to measure aerobic fitness similarly to the 20MSR but may also be used as a field test of the ability to repeat high-intensity efforts.
To quantify the changes of hemoglobin mass (Hbmass) and maximum oxygen consumption (VO2max) after 22 days training at 1300-1800 m combined with nightly exposure to 3000-m simulated altitude. We hypothesized that with simulated 3000-m altitude, an adequate beneficial dose could be as little as 10 h/24 h.
Fourteen male collegiate runners were equally divided into 2 groups: altitude (ALT) and control (CON). Both groups spent 22 days at 1300-1800 m. ALT spent 10 h/night for 21 nights in simulated altitude (3000 m), and CON stayed at 1300 m. VO2max and Hbmass were measured twice before and once after the intervention. Blood was collected for assessment of percent reticulocytes (%retics), serum erythropoietin (EPO), ferritin, and soluble transferrin receptor (sTfR) concentrations.
Compared with CON there was an almost certain increase in absolute VO2max (8.6%, 90% confidence interval 4.8-12.6%) and a likely increase in absolute Hbmass (3.5%; 0.9-6.2%) at postintervention. The %retics were at least very likely higher in ALT than in CON throughout the 21 nights, and sTfR was also very likely higher in the ALT group until day 17. EPO of ALT was likely higher than that of CON on days 1 and 5 at altitude, whereas serum ferritin was likely lower in ALT than CON for most of the intervention.
Together the combination of the natural and simulated altitude was a sufficient total dose of hypoxia to increase both Hbmass and VO2max.
To quantify the changes of hemoglobin mass (Hb mass ) and maximum oxygen consumption (VO 2max ) after 22 days training at 1300–1800 m combined with nightly exposure to 3000-m simulated altitude. We hypothesized that with simulated 3000-m altitude, an adequate beneficial dose could be as little as 10 h/24 h.
Fourteen male collegiate runners were equally divided into 2 groups: altitude (ALT) and control (CON). Both groups spent 22 days at 1300–1800 m. ALT spent 10 h/night for 21 nights in simulated altitude (3000 m), and CON stayed at 1300 m. VO 2max and Hb mass were measured twice before and once after the intervention. Blood was collected for assessment of percent reticulocytes (%retics), serum erythropoietin (EPO), ferritin, and soluble transferrin receptor (sTfR) concentrations.
Compared with CON there was an almost certain increase in absolute VO 2max (8.6%, 90% confidence interval 4.8–12.6%) and a likely increase in absolute Hb mass (3.5%; 0.9–6.2%) at postintervention. The %retics were at least very likely higher in ALT than in CON throughout the 21 nights, and sTfR was also very likely higher in the ALT group until day 17. EPO of ALT was likely higher than that of CON on days 1 and 5 at altitude, whereas serum ferritin was likely lower in ALT than CON for most of the intervention.
Together the combination of the natural and simulated altitude was a sufficient total dose of hypoxia to increase both Hb mass and VO 2max .
To date, there is limited research examining the influence of pacing pattern (PP) on middle distance swimming performance. As such, the purpose of the present study was to examine the influence of PP manipulation on 400 m freestyle swimming performance.
15 front-crawl swimmers (5 female, 10 male, age: 18±2 y) performed three simulated 400 m swimming events. The initial trial was self-selected pacing (PPSS). The following two trials were performed in a counter-balanced order and required participants to complete the first 100m slower (PPslow: 4.5±2.2 %) or faster (PPfast: 2.4±1.6%) than the self-paced trial. 50m split times were recorded during each trial.
Overall performance time was faster in PPSS (275.0±15.9 s) compared with PPfast (278.5±16.4 s, (p=0.05) but not significantly different to PPslow (277.5±16.2 s, p=0.22). However, analysis for practical relevance revealed that pacing manipulation resulted in a 'likely' (> 88.2 %) decrease in performance compared with the PPSS.
Moderate manipulation of the starting speed during simulated 400 m freestyle races seems to affect overall performance. The observed results indicate that self-selected pacing is optimal in most individuals, yet it seems to fail in some swimmers. Hence future research should focus on the identification of those athletes possibly profiting from manipulations.
Previously it has been observed that, in well-trained 800-m athletes, VO2max is not attained during middle-distance running events on a treadmill, even when a race-type pacing strategy is adopted. Therefore, the authors investigated whether specialization in a particular running distance (400-m or 800-m) influences the VO2 attained during running on a treadmill.
Six 400-m and six 800-m running specialists participated in the study.A 400-m trial and a progressive test to determine VO2max were completed in a counterbalanced order. Oxygen uptakes attained during the 400-m trial were compared to examine the influence of specialist event.
A VO2 plateau was observed in all participants for the progressive test, demonstrating the attainment of VO2max. The VO2max values were 56.2 +/- 4.7 and 69.3 +/- 4.5 mL x kg-1 x min-1 for the 400-m- and 800-m-event specialists, respectively (P = .0003). Durations for the 400-m trial were 55.1 +/- 4.2 s and 55.8 +/- 2.3 s for the 400-m- and 800-m-event specialists, respectively. The VO2 responses achieved were 93.1% +/- 2.0% and 85.7% +/- 3.0% VO2max for the 400-m- and 800-m-event specialists, respectively (P = .001).
These results demonstrate that specialist running events do appear to influence the percentage of VO2max achieved in the 400-m trial, with the 800-m specialists attaining a lower percentage of VO2max than the 400-m specialists. The 400-m specialists appear to compensate for a lower VO2max by attaining a higher percentage VO2max during a 400-m trial.
Iliac blood flow restrictions causing painful and "powerless" legs are often attributed to overtraining and may develop for some time before being correctly diagnosed. In the current study, differences between actual performance parameters and performance parameters predicted from the Lamberts and Lamberts Submaximal Cycle test (LSCT-predicted) were studied in a world class cyclist with bilateral kinking of the external iliac artery before and after surgery. Two performance testing sessions, including a peak power output (PPO) and a 40km time trial (40km TT) tests were conducted before surgery, while one testing session was conducted after the surgery. Actual vs. LSCT-predicted performance parameters in the world class cyclists were compared to 82 symptom-free, trained-to-elite male cyclists. No differences were found between actual and LSCT-predicted PPO before and after surgical interventions. However, there were differences between actual and LSCT-predicted 40km TT time in the tests performed before the surgery (2:51(min:s) and 2:55(min:s), respectively). These differences were no longer apparent in the post-surgery 40km TT (2 s). This finding suggests that iliac blood flow restrictions seem to mainly impair endurance performance rather than peak cycling performance. A standard PPO test without brachial ankle blood pressure measurements might not be able to reflect iliac blood flow restrictions. Differences between actual and LSCT-predicted 40km TT time may assist in the earlier referral to a cardiovascular specialist and result the earlier detection of iliac blood flow restrictions.
During the competitive soccer season, women's intercollegiate matches are typically played on Friday evenings and Sunday afternoons. The efficacy of a 42-h recovery period is not well understood. This investigation was conducted to determine performance differences between Friday and Sunday matches during a competitive season.
Ten NCAA Division I female soccer players (20.5±1.0 y, 166.6±5.1 cm, 61.1±5.8 kg) were monitored with 10-Hz GPS devices across 8 weekends with matches played on Friday evenings and Sunday afternoons. The players were outside backs, midfielders, and forwards. All players had to participate in a minimum of 45 min/match to be included in the study. Average minutes played, total distance covered, total distance of high-intensity running (HIR) (defined as running at a velocity equal to or exceeding 3.61 m/s for longer than 1 s), the number of HIR efforts, and the number of sprints were calculated for each match. Data for Friday vs Sunday matches were averaged and then compared using dependent t tests.
No differences were seen in minutes played, distance rate, or number of sprints between Friday and Sunday matches. A significant (P=.017) decrease in rate of HIR between Friday (25.37±7.22 m/min) and Sunday matches (22.90±5.70 m/min) was seen. In addition, there was a trend toward a difference (P=.073) in the number of efforts of HIR between Friday (138.41±36.43) and Sunday (126.92±31.31).
NCAA Division I female soccer players cover less distance of HIR in games played less than 48 h after another game. This could be due to various factors such as dehydration, glycogen depletion, or muscle damage.
The aim of the study was to examine the effect of fatigue, developed during prolonged high-intensity intermittent exercise, on the performance of soccer shooting and dribbling skill.
Nine semiprofessional soccer players with a mean age of 20.7+/-1.4 years volunteered to participate in the study. Participants completed a slalom dribble test and the Loughborough Soccer Shooting Test (LSST), before and directly following the performance of three 15-min bouts of a modified version of the Loughborough Intermittent Shuttle Test (LIST).
Mean heart rates and mean 15-m sprint times remained unchanged across the three bouts of the LIST. Following the LIST slalom dribbling time increased significantly by 4.5+/-4.0% (P=.009), while the mean total points scored during the LSST was significantly reduced by 7.6+/-7.0 points (P=.012). When fatigued the frequency of shots in the LSST achieving the highest score of 5 points was reduced by 47% while the frequency of shots achieving the lowest 0 point score increased by 85%.
Results show that while 45 min of exercise caused no decrements in sprint performance there were significant reductions in the ability to perform soccer-specific skills. Both the speed (dribbling time) and accuracy (shot performance) with which soccer-specific skills were executed was impaired following exercise replicating one-half of a soccer match.
The aim of this study was to examine the reliability and validity of a popular field test for aerobic fitness used in soccer (45-15) in Italy. Alternating progressive 45-s runs with 15 s passive recovery until exhaustion, the test considers peak speed (PS) as a reflection of maximal aerobic speed (MAS). The validity and reliability of the 45-15 was assessed in 18 young male soccer players (age 16.7 ± 1.8 y, body mass 70 ± 7.45 kg, height 177 ± 0.5 cm, 55.62 ± 5.56 mL · kg1 · min1) submitted to laboratory testing for aerobic fitness and repeatedly to the 45-15. Results showed that 45-15 PS was significantly related to VO2max (r = .80, P < .001, 95%CI .47-.93) and MAS (r = .78, P = .001, 95%CI .43-.93). No significant bias between MAS 45-15 PS (P = .11) was found during the measurement-consistency study. Receiver-operating-characteristic (ROC) analysis showed that 45-15 PS was sensitive in detecting VO2max changes in subjects as revealed by area under the curve (.97; 95%CI .73-1). Players with peak 45-15 speed equal to or above 16.5 km/h (ie, ROC cutoff) may be considered to have good aerobic fitness. In light of this study's findings, the 45-15 test may be considered a reliable and valid test to evaluate meaningful information to direct generic aerobic training in soccer.
Initial 14-m start performance has substantial influence on 500 m race outcome at the international level yet the relationship has not been systematically quantified. The purpose of this investigation was to examine the relationship between rank position entering first corner (RPEFC) and race outcome and to understand how this relationship changes with competition round and absolute race intensity. Data were compiled from 2011-2014 World Cup seasons and 2010 and 2014 Olympic Winter Games. Association between RPEFC and race outcome was determined through Kendall's tau rank correlations. A visual comparison was made of how the relationship changes with relative competition level (race tau correlations were sorted by competition round), and with race intensity (race tau correlations were sorted by within-event winning time). A very large relationship between RPEFC and race outcome was observed (correlations for; cohort: T=0.60, men: T=0.53 and women: T=0.67). When examined by competition round (quarter- to A-finals), no substantial change in relationship was observed (men: T=0.57 to 0.46; and women: T=0.73 to 0.53). However, when the start performance relationship was considered by within-event winning time, the relationship strength increased with decreasing time (men: T=0.61 to T=0.46; women: T=0.76 to T=0.57, fastest to 7th and 8th fastest combined respectively). These results establish and quantify RPEFC as an important aspect of elite short track 500 m race outcome. RPEFC as an indicator of race outcome becomes increasingly important with absolute race intensity suggesting that RPEFC capability is a discriminating factor for competitors of similar top speed and speed endurance capabilities.
To determine the swimmer's anaerobic potential and better plan training, understanding physiological effects of the fatigue is essential.
Study changes in the characteristics of the intra-cyclic velocity variation during an all-out 50m swim and to observe differences in speed and stroking parameters between these changes.
28 competitive swimmers performed a 50m front crawl all-out test attached to a speedometer. The v(t) curve off all stroke cycles was analyzed per individual using a routine that included a wavelet procedure, allowing the determination of the fatigue thresholds that divides effort in time intervals.
One or two fatigue thresholds were observed at individual level on the v(t) curve. In males, when one fatigue threshold was identified, the mean velocity and the stroke index dropped (p<0.05) in the second time interval (1.7±0.0 vs. 1.6±0.0m.s-1 and 3.0±0.2 vs. 2.8±0.3m.s-1, respectively). When two fatigue thresholds were identified, the mean velocity of the first time interval was higher than that of the third time interval (p<0.05), both for male (1.7±0.0 vs. 1.6±0.1m.s-1) and female (1.5±0.1 vs. 1.3±0.1m.s-1) swimmers.
One or two fatigue thresholds were found in the intra-cyclic velocity variation patterns. Concurrently, changes in velocity and stroke parameters were also observed between time intervals. This information could allow the coach to obtain new insights in delaying the degenerative effects of fatigue and maintain stable stroke cycle characteristics over a 50m event.
The effect of a prolonged running trial on the energy cost of running (Cr) during a 60-km ultra marathon simulation at the pace of a 100-km competition was investigated in 13 men (40.8 yy ± 5.6; 70.7 kg ± 5.5; 177.5 cm ± 4.5) and 5 women (40.4 yy ± 2.3; 53.7 kg ± 4.4; 162.4 cm ± 4.8) who participated in a 60-km trial consisting of 3 consecutive 20-km laps. VO2 at steady state was determined at constant speed before the test and at the end of each lap; stride length (SL) and frequency (SF) and contact time (CT) were measured at the same time points; Serum creatine kinase (S-CPK) was measured before and at the end of the test. Cr in J kg-1 m-1, as calculated from VO2ss and respiratory exchange ratio, did not increased with distance. SL significantly decreased with distance. The net increase in S-CPK was linearly related with the percent increase of Cr observed during the trial. It is concluded that, in spite of increased S-CPK, this effort was not able to elicit any peripheral or central fatigue leading or biomechanical adaptation leading to any modification of Cr.
The aim of this study was to investigate the effects of a maximal repeated-jumps task on force production, muscle activation and kinematics, and to determine if changes in performance were dependent on gender.
Eleven male and nine female athletes performed continuous countermovement jumps for 60 s on a force platform while muscle activation was assessed using surface electromyography. Performances were videotaped and digitized (60 Hz). Data were averaged across three jumps in 10-s intervals from the initial jump to the final 10 s of the test.
No interaction between time and gender was evident for any variable; therefore, all results represent data collapsed across gender. Preactivation magnitude decreased across time periods for anterior tibialis (AT, P < .001), gastrocnemius (GAS, P < .001) and biceps femoris (BF, P = .03), but not for vastus lateralis (VL, P = .16). Muscle activation during ground contact did not change across time for BF; however, VL, G, and AT showed significant reductions (all P < .001). Peak force was reduced at 40 s compared with the initial jumps, and continued to be reduced at 50 and 60 s (all P < .05). The time from peak force to takeoff was greater at 50 and 60 s compared with the initial jumps (P < .05). Both knee flexion and ankle dorsiflexion were reduced across time (both P < .001), whereas no change in relative hip angle was evident (P = .10). Absolute angle of the trunk increased with time (P < .001), whereas the absolute angle of the shank decreased (P < .001).
In response to the fatiguing task, subjects reduced muscle activation and force production and altered jumping technique; however, these changes were not dependent on gender.
Self-report (SR) has been the primary method used to assess fluid intake during endurance events, but unfortunately, little is known about the validity of SR. The purpose of this study was to compare SR fluid intake to direct-measurement (DM) during the run of a 70.3-mile triathlon.
Fifty-three (42 men, 11 women) individuals competing in a 70.3-mile triathlon participated in the study. On the 13.1-mile run, 11 research stations provided fluid in bottles filled with 163 ml of water or carbohydrate-electrolyte beverage (CEB). Participants submitted bottles 25 meters past aid stations to be reweighed post-race. Participants also answered questions regarding fluid intake post-race. Bland-Altman plots and 95% limits of agreement (LOA) were used to assess precision of the measures, while least-squares regression assessed linear agreement.
SR intakes during the run ranged from 0-1793, 0-1837, and 0-2628 ml for water, CEB, and total fluid, with corresponding DM intakes of 0-1599, 0-1642, and 0-2250 ml. DM and SR showed strong linear agreement for water, CEB, and total fluid (R2 = 0.71, 0.80, and 0.80). Mean differences between the measures on the Bland-Altman plots were small (13-41 ml), but relatively large differences (± 500 ml) between the measures were apparent for some participants.
SR is the predominant methodology used in field studies assessing hydration, despite little-to-no data confirming its validity. The results herein suggest that choosing a fluid intake assessment methodology should be done on a case-by-case basis and that caution should be utilized when interpreting data based on SR.