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Marcus P. Tartaruga, Carlos B. Mota, Leonardo A. Peyré-Tartaruga and Jeanick Brisswalter

Purpose:

To identify the effect of allometric scaling on the relationship between running efficiency (R Eff) and middle-distancerunning performance according to performance level.

Methods:

Thirteen male recreational middle-distance runners (mean ± SD age 33.3 ± 8.4 y, body mass 76.4 ± 8.6 kg, maximal oxygen uptake [VO2max] 52.8 ± 4.6 mL · kg−1 · min−1; G1) and 13 male high-level middle-distance runners (age 25.5 ± 4.2 y, body mass 62.8 ± 2.7 kg, VO2max 70.4 ± 1.9 mL · kg−1 · min−1; G2) performed a continuous incremental test to volitional exhaustion to determine VO2max and a 6-min submaximal running test at 70% of VO2max to assess R Eff.

Results:

Significant correlation between R Eff and performance were found for both groups; however, the strongest correlations were observed in recreational runners, especially when using the allometric exponent (respectively for G1, nonallometric vs allometric scaling: r = .80 vs r = .86; and for G2, nonallometric vs allometric scaling: r = .55 vs r = .50).

Conclusion:

These results indicate that an allometric normalization may improve endurance-performance prediction from R Eff values in recreational, but not in elite, runners.

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Jasper Reenalda, Maurice T.F. Maas and Jos J. de Koning

Purpose:

To examine the influence of induced changes in the morphology of the leg by adding mass on the optimal step length (OSL) in experienced runners to get more insight into parameters that influence preferred step length (PSL) and OSL.

Methods:

Thirteen experienced male runners (mean age 26.9 ± 6.1 y, height 183.7 ± 7.1 cm, mass 71.8 ± 5.9 kg) ran on a treadmill in 3 different conditions: unloaded (UL), loaded with 2 kg mass at the ankles (MA), and loaded with 2 kg mass at the hips (MH) at 7 different step lengths (SLs). SL deviations were expressed as deviations in relative leg length (%LL) from the individual PSL: 0%LL, ±5%LL, ±10%LL, and ±15%LL. Trials lasted 8 min, and 8 min of rest was given between trials. Oxygen uptake (V̇O2) was expressed as a fraction of V̇O2 at PSL + 0%LL in the unloaded condition (%V̇O2). The %SL with the lowest value of %V̇O2 was considered the OSL for this group of participants.

Results:

OSL at the UL condition was 6% shorter than PSL. The MA condition resulted in a 7%LL larger OSL than at UL and MH (P < .05).

Conclusions:

The mass distribution of the leg is a determinant of the OSL. As a consequence of the added mass to the ankles, OSL was 7%LL longer. Morphological characteristics of the leg might therefore play an important role in determining the runner’s individual optimal SL.

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Sara López-Martínez, Mairena Sánchez-López, Montserrat Solera-Martinez, Natalia Arias-Palencia, Rosa M. Fuentes-Chacón and Vicente Martínez-Vizcaíno

Purpose:

Our objective was to analyze the association between different intensities of physical activity (PA), physical fitness, and metabolic syndrome (MS) in young adults.

Methods:

Cross-sectional study including 275 university students, 18–30 years old, from Cuenca, Spain. We evaluated (a) physical activity using accelerometry, (b) aerobic capacity (VO2max), and (c) muscle strength, by a muscle strength index calculated as the sum of the standardized z score of handgrip dynamometry/weight and standing broad jump. An MS index was estimated by summing standardized z scores of waist circumference, ratio of triglycerides to high-density lipoprotein, mean arterial blood pressure, and HOMA-IR.

Results:

The mean scores of MS index and HOMAIR were significantly higher and the VO2max significantly lower for individuals who did not perform 20 min or more per week of vigorous physical activity. However, those who performed 250 min/week of moderate physical activity showed no significant differences in either VO2max or the MS index when compared with individuals who did not perform this level of activity. The MS index was lower in those with medium-high levels of aerobic capacity. In addition, individuals with medium-high levels of muscular fitness showed lower waist circumference and a lower MS index.

Conclusions:

VO2max and muscle strength are negatively associated with metabolic risk. 20-min/week of vigorous physical activity was associated with lower cardiometabolic risk in young adults; moderate physical activity did not show association with lower cardiometabolic risk.

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Ine Wigernæs, Sigmund B. Strømme and Arne T. Høstmark

The present study investigated the effect of active recovery (AR) as compared to rest recovery (RR) upon FFA concentrations following moderate- (MI) or high-intensity (HI) running. Fourteen well-trained males (23.7±6 years. V̇O2max = 69.5±1.8ml · min−1kg−1) were randomly assigned into two trials (HI = 30 min at 82% of V̇O2max; MI = 60 min at 75% of V̇O2max). Within each group, the subject completed two sets of experiments of running followed by either AR (15 min running at 50% of V̇O2max) or RR (complete rest in the supine position). Plasma volume changes after the exercise did not deviate between the AR or RR trials. In both the HI and Ml trials, AR resulted in lower FFA peaks and lower overall FFA concentrations while performing AR (p<.05). However, upon discontinuing AR. there was a rise in the FFA concentration. At 120-min post-exercise, the FFA concentrations after AR and RR were not significantly different. The changes in the FFA/albumin ratio were similar to the FFA responses. It is concluded that AR may counteract the rise in FFA 5–15 minutes after exercise.

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Michail Lubomirov Michailov, Audry Morrison, Mano Mitkov Ketenliev and Boyanka Petkova Pentcheva

Traditional treadmill or bicycle ergometry neglects the upper-body musculature that predominantly limits or terminates rock-climbing performance (ie, the inability to continually pull up one’s body mass or “hang on”).

Purpose:

To develop an incremental maximal upper-body ergometer test (UBT) to evaluate climbers’ aerobic fitness and sport-specific work capacity and to compare these results with a traditional treadmill protocol.

Methods:

Eleven elite sport climbers (best redpoint grade Fr.8b) performed a UBT on a vertically mounted rowing ergometer and, on a separate occasion, performed a maximal incremental treadmill test (TMT). Cardiorespiratory parameters were measured continuously. Lactate (La) samples were collected.

Results:

Peak oxygen consumption (VO2peak) and heart rate in UBT and TMT were 34.1 ± 4.1 vs 58.3 ± 2.6 mL · min−1 · kg−1 and 185 ± 8 vs 197 ± 8 beats/min, respectively, and both variables were of significantly lower magnitude during UBT (P < .001). End-of-test La levels for UBT (11.9 ± 1.7 mmol/L) and TMT (12.3 ± 2.5 mmol/L) were similar (P = .554). Treadmill VO2peak was not correlated with either upper-body (UB) VO2peak (P = .854) or redpoint and on-sight climbing grade ability (P > .05). UB VO2peak and peak power output per kg body mass were both strongly correlated (P < .05) with climbing grade ability. The highest correlation coefficient was calculated between current on-sight grade and UB VO2peak (r = .85, P = .001).

Conclusion:

UBT aerobic- and work-capacity results were strongly correlated to climbing-performance variables and reflected sport-specific fatigue, and TMT results were not. UBT is preferred to TMT to test and monitor dedicated and elite rock climbers’ training status.

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Jeffrey E. Herrick, Judith A. Flohr, Davis L. Wenos and Michael J. Saunders

Purpose:

This study compared the metabolic and performance effects of riding front-only suspension (FS) and front-and-rear suspension (FRS) mountain bicycles on an off-road course that simulated competitive cross-country race conditions (>105 min in duration, with ∼70% of time spent riding uphill).

Methods:

Seven competitive mountain bikers (73.8 ± 7.6 kg; 61.0 ± 4.3 mL·kg–1·min–1) completed two randomized FS and FRS trials. Bikes were similar, excluding rear wheel suspension on the FRS, which increased bike weight by ∼2 kg. Each trial consisted of four laps of rugged 8 km trail with 154 m of elevation gain per lap. The first three laps were performed at ∼70% of VO2max; VO2, HR, and RPE were collected during the first and third laps. The final lap was performed as a maximal time-trial effort.

Results:

During the first and third laps, VO2, HR, and RPE were similar between FS and FRS. However, FS was significantly faster than FRS during the ascending segment of the course (17.6 ± 2.9 vs 18.9 ± 3.4 min, P = .035), despite similar VO2 (P = .651). Although not statistically significant, FRS tended to be faster than FS during the descending portion of the course (8.1 ± 2.0 vs 9.1 ± 2.1, P = .067) at similar VO2. Performance during the final time-trial lap was significantly faster for FS than FRS (24.9 ± 3.9 min, 27.5 ± 4.9 min, P = .008).

Conclusion:

FS was faster than FRS over a course that simulated competitive cross-country race conditions. The faster times were likely the result of improved cycling economy during ascending, which were at least partially influenced by the lighter weight of the FS.

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Louise Croft, Suzanne Dybrus, John Lenton and Victoria Goosey-Tolfrey

Purpose:

To examine the physiological profiles of wheelchair basketball and tennis and specifically to: (a) identify if there are differences in the physiological profiles of wheelchair basketball and tennis players of a similar playing standard, (b) to determine whether the competitive physiological demands of these sports differed (c) and to explore the relationship between the blood lactate [Bla] response to exercise and to identify the sport specific heart rate (HR) training zones.

Methods:

Six elite athletes (4 male, 2 female) from each sport performed a submaximal and VO2 peak test in their sport specific wheelchair. Heart rate, VO2, and [Bla] were measured. Heart rate was monitored during international competitions and VO2 was calculated from this using linear regression equations. Individual HR training zones were identified from the [Bla–] profile and time spent within these zones was calculated for each match.

Results:

Despite no differences in the laboratory assessment of HRpeak, the VO2peak was higher for the basketball players when compared with the tennis players (2.98 ± 0.91 vs 2.06 ± 0.71; P = .08). Average match HR (163 ± 11 vs 146 ± 16 beats-min–1; P = .06) and average VO2 (2.26 ± 0.06 vs 1.36 ± 0.42 L-min-1; P = .02) were higher during actual playing time of basketball when compared with whole tennis play. Consequently, differences in the time spent in the different training zones within and between the two sports existed (P < .05).

Conclusions:

Wheelchair basketball requires predominately high-intensity training, whereas tennis training requires training across the exercise intensity spectrum.

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Matthew W. Driller, James W. Fell, John R. Gregory, Cecilia M. Shing and Andrew D. Williams

Purpose:

Several recent studies have reported substantial performance and physiological gains in well-trained endurance runners, swimmers, and cyclists following a period of high-intensity interval training (HIT). The aim of the current study was to compare traditional rowing training (CT) to HIT in well-trained rowers.

Methods:

Subjects included 5 male and 5 female rowers (mean ± SD; age = 19 ± 2 y; height = 176 ± 8 cm; mass = 73.7 ± 9.8 kg; Vo2peak = 4.37 ± 1.08 L·min−1). Baseline testing included a 2000-m time trial and a maximal exercise test to determine Vo2peak, 4-min all-out power, and 4 mmol·L−1 blood lactate threshold. Following baseline testing, rowers were randomly allocated to HIT or CT, which they performed seven times over a 4-wk period. The HIT involved 8 × 2.5-min intervals at 90% of the velocity maintained at Vo2peak, with individual recoveries returning to 70% of the subjects’ maximal heart rate between intervals. The CT intensity consisted of workloads corresponding to 2 and 3 mmol·L−1 blood lactate concentrations. On completion of HIT or CT, rowers repeated the testing performed at baseline and were then allocated to the alternative training program and completed a crossover trial.

Results:

HIT produced greater improvements in 2000-m time (1.9 ± 0.9%; mean ± SD), 2000-m power (5.8 ± 3.0%), and relative Vo2peak (7.0 ± 6.4%) than CT.

Conclusion:

Four weeks of HIT improves 2000-m time-trial performance and relative Vo2peak in competitive rowers, more than a traditional approach.

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Tom J. Hazell, T. Dylan Olver, Craig D. Hamilton and Peter W. R. Lemon

Six weeks (3 times/wk) of sprint-interval training (SIT) or continuous endurance training (CET) promote body-fat losses despite a substantially lower training volume with SIT. In an attempt to explain these findings, the authors quantified VO2 during and after (24 h) sprint-interval exercise (SIE; 2 min exercise) vs. continuous endurance exercise (CEE; 30 min exercise). VO2 was measured in male students (n = 8) 8 times over 24 hr under 3 treatments (SIE, CEE, and control [CTRL, no exercise]). Diet was controlled. VO2 was 150% greater (p < .01) during CEE vs. SIE (87.6 ± 13.1 vs. 35.1 ± 4.4 L O2; M ± SD). The observed small difference between average exercise heart rates with CEE (157 ± 10 beats/min) and SIE (149 ± 6 beats/min) approached significance (p = .06), as did the difference in peak heart rates during CEE (166 ± 10 beats/min) and SIE (173 ± 6 beats/min; p = .14). Total O2 consumed over 8 hr with CEE (263.3 ± 30.2 L) was greater (p < .01) than both SIE (224.2 ± 15.3 L; p < .001) and CTRL (163.5 ± 16.1 L; p < .001). Total O2 with SIE was also increased over CTRL (p < .001). At 24 hr, both exercise treatments were increased (p < .001) vs. CTRL (CEE = 500.2 ± 49.2; SIE = 498.0 ± 29.4; CTRL = 400.2 ± 44.6), but there was no difference between CEE and SIE (p = .99). Despite large differences in exercise VO2, the protracted effects of SIE result in a similar total VO2 over 24 hr vs. CEE, indicating that the significant body-fat losses observed previously with SIT are partially due to increases in metabolism postexercise.

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Devin G McCarthy and Lawrence L Spriet

Rest between training sessions can be short for athletes. In these situations, consuming carbohydrate (CHO) post-exercise replenishes glycogen stores, which is important for recovery and subsequent performance.

Purpose:

This study tested whether CHO intake during a 2-h rest between exercise bouts improved performance in the subsequent bout.

Methods:

In a randomized, single-blinded, crossover design, 10 recreationally-active participants (23 ± 4 yr, 70.8 ± 6.6 kg, VO2peak:47.0 ± 5.4 mL O2·min-1·kg body mass-1) arrived at the lab post-prandial and completed 2 exercise bouts separated by 2-h rest. Bouts included 5 x 4-min intervals at ~80% VO2peak separated by 2-min at ~40% VO2peak and ended with an endurance trial (ET) to voluntary exhaustion at ~90% VO2peak. During intervals 1 and 4 in each bout expired gases were collected and O2 deficit was estimated. Immediately following bout-1, either a CHO (1.2 g CHO·kg body mass-1) or placebo (PL) solution was consumed.

Results:

ET duration decreased in bout-2 vs. 1 in both conditions (P<0.01) but was ~35% longer in bout-2 with CHO vs. PL (Interaction, P=0.03; post-hoc, P=0.03). VO2 increased during interval 4 vs. 1 in both bouts (P<0.01) but was unaffected by CHO (P≥0.58). O2 deficit was unaffected by CHO (P=0.93), bout or interval (P≥0.15). Perceived exertion was higher in bout-2 vs. 1 (P<0.001) and reduced in intervals 2 and 4 in CHO (P≤0.01).

Conclusions:

When rest between training sessions is 2 hours, athletes may improve subsequent performance by consuming CHO during recovery. Supported by NSERC, Canada.