The effect of exercise modality on respiratory muscle performance in triathletes

Transferability of Cardiopulmonary Parameters between Treadmill and Cycle Ergometer Testing in Male Triathletes-Prediction Formulae

Cardiopulmonary exercise testing (CPET) on a treadmill (TE) or cycle ergometry (CE) is a common method in sports diagnostics to assess athletes' aerobic fitness and prescribe training. In a triathlon, the gold standard is performing both CE and TE CPET. The purpose of this research was to create models using CPET results from one modality to predict results for the other modality. A total of 152 male triathletes (age = 38.20 ± 9.53 year; BMI = 23.97 ± 2.10 kg·m-2) underwent CPET on TE and CE, preceded by body composition (BC) analysis. Speed, power, heart rate (HR), oxygen uptake (VO2), respiratory exchange ratio (RER), ventilation (VE), respiratory frequency (fR), blood lactate concentration (LA) (at the anaerobic threshold (AT)), respiratory compensation point (RCP), and maximum exertion were measured. Random forests (RF) were used to find the variables with the highest importance, which were selected for multiple linear regression (MLR) models. Based on R2 and RF variable selection, MLR equations in full, simplified, and the most simplified forms were created for VO2AT, HRAT, VO2RCP, HRRCP, VO2max, and HRmax for CE (R2 = 0.46-0.78) and TE (R2 = 0.59-0.80). By inputting only HR and power/speed into the RF, MLR models for practical HR calculation on TE and CE (both R2 = 0.41-0.75) were created. BC had a significant impact on the majority of CPET parameters. CPET parameters can be accurately predicted between CE and TE testing. Maximal parameters are more predictable than submaximal. Only HR and speed/power from one testing modality could be used to predict HR for another. Created equations, combined with BC analysis, could be used as a method of choice in comprehensive sports diagnostics.

The Effect of an Olympic Distance Triathlon on Pulmonary Diffusing Capacity and its Recovery 24 Hours Later

The Olympic distance triathlon includes maximal exercise bouts with transitions between the activities. This study investigated the effect of an Olympic distance triathlon (1.5-km swim, 40-km bike, 10-km run) on pulmonary diffusion capacity (DLCO). In nine male triathletes (age: 24 ± 4.7 years), we measured DLCO and calculated the DLCO to alveolar volume ratio (DLCO/VA) and performed spirometry testing before a triathlon (pre-T), 2 hours after the race (post-T), and the day following the race (post-T-24 h). DLCO was measured using the 9-s breath-holding method. We found that (1) DLCO decreased significantly between pre- and post-T values (38.52 ± 5.44 vs. 35.92 ± 6.63 ml∙min^-1∙mmHg^-1) (p < 0.01) and returned to baseline at post-T-24 h (38.52 ± 5.44 vs. 37.24 ± 6.76 ml∙min^-1∙mmHg^-1, p > 0.05); (2) DLCO/VA was similar at the pre-, post- and post-T-24 h DLCO comparisons; and (3) forced expiratory volume in the first second (FEV₁) and mean forced expiratory flow during the middle half of vital capacity (FEF25-75%) significantly decreased between pre- and post-T and between pre- and post-T-24-h (p < 0.02). In conclusion, a significant reduction in DLCO and DLCO/VA 2 hours after the triathlon suggests the presence of pulmonary interstitial oedema. Both values returned to baseline 24 hours after the race, which reflects possible mild and transient pulmonary oedema with minimal physiological significance.

The effect of an Olympic distance triathlon on the respiratory muscle strength and endurance in triathletes

High-intensity exercise, marathons, and long distances triathlons have been shown to induce the fatigue of respiratory muscles (RMs). Never-theless, fatigue and the recovery period have not been studied in re-sponse of an Olympic distance triathlon (1.5-km swim, 40-km bike, 10-km run: short-distance triathlon). The aim of this study was to evaluate the RM fatigue induced by an Olympic distance triathlon. Nine male triath-letes (24±1.1 years) underwent spirometric testing and the assessment of RM performance. Respiratory function tests were conducted in sit-ting position. Spirometric parameters, maximal inspiratory and expirato-ry pressures, and RM endurance assessed by measuring the time limit were evaluated before (pre-T), after (post-T), and the day following the triathlon (post-T-24 hr). Residual volume increased: pre-T vs. post-T (P<0.002), maximal inspiratory pressure significantly decreased from 127.4±17.2 (pre-T) to 121.6±18.5 cmH₂O (post-T) (P<0.001) and returned to the pre-T value 24 hr after the race (125.0±18.6). RM endurance sig-nificantly decreased from 4:51±0:8 (pre-T) to 3:13±0:7 min (post-T, P< 0.001) and then remained decreased for 24 hr after the race from 4:51± 0:8 (pre-T) to 3:39±0:4 min 24 hr after (P<0.002). Both, strength and en-durance of inspiratory muscles decrease after Olympic distance triath-lon. Furthermore, the impaired of inspiratory muscle endurance 24 hr after the race suggested a slow recovery and persistence of inspiratory muscle fatigue.

Effects of inspiratory muscle warm-up on locomotor muscle oxygenation in elite speed skaters during 3000 m time trials

PURPOSE

It has been shown that an inspiratory muscle warm-up (IMW) could enhance performance. IMW may also improve the near-infrared spectroscopy (NIRS)-derived tissue oxygen saturation index (TSI) during cycling. However, there exists contradictory data about the effect of this conditioning strategy on performance and muscle oxygenation. We examined the effect of IMW on speed skating performance and studied the underpinning physiological mechanisms related to muscle oxygenation.

METHODS

In a crossover, randomized, single-blind study, eight elite speed skaters performed 3000 m on-ice time trials, preceded by either IMW (2 × 30 breaths, 40% maximal inspiratory pressure) or SHAM (2 × 30 breaths, 15% maximal inspiratory pressure). Changes in TSI, oxyhemoglobin-oxymyoglobin ([O₂HbMb]), deoxyhemoglobin-deoxymyoglobin ([HHbMb]), total hemoglobin-myoglobin ([THbMb]) and HHbMbdiff ([O₂HbMb]-[HHbMb]) in the right vastus lateralis muscle were monitored by NIRS. All variables were compared at different time points of the race simulation with repeated-measures analysis of variance. Differences between IMW and SHAM were also analyzed using Cohen's effect size (ES) ± 90% confidence limits, and magnitude-based inferences.

RESULTS

Compared with SHAM, IMW had no clear impact on skating time (IMW 262.88 ± 17.62 s vs. SHAM 264.05 ± 21.12 s, effect size (ES) 0.05; 90% confidence limits, - 0.22, 0.32, p = 0.7366), TSI, HbMbdiff, [THbMb], [O₂HbMb] and perceptual responses.

CONCLUSIONS

IMW did not modify skating time during a 3000 m time trial in speed skaters, in the conditions of our study. The unchanged [THbMb] and TSI demonstrate that the mechanisms by which IMW could possibly exert an effect on performance were unaffected by this intervention.

Inspiratory muscle warm-up attenuates muscle deoxygenation during cycling exercise in women athletes

This study examines the effects of inspiratory muscle warm-up (IMW) on performance and muscle oxygenation during cycling exercise. In a randomized crossover study of 10 female soccer players, the IMW, placebo (IMWP) and control (CON) trials were conducted before two 6-min submaximal cycling exercises (100 and 150W) followed by intermittent high-intensity sprint (IHIS, 6×10s with 60s recovery). The reduction in tissue saturation index (TSI) in legs in the IMW were significantly less than those in IMWP and CON (P<0.01) during submaximal cycling exercises. The average reduction in TSI during the IHIS test with IMW was significantly less than those in the IMWP and CON (P=0.023). Nevertheless, the IHIS performance with IMW did not differ from that in other trials. In conclusion, the leg TSI during continuous submaximal cycling exercise followed by intermittent sprinting was likely improved by specific IMW (40% maximal inspiratory mouth pressure), which did not enhance IHIS performance.

Diagnosis and management of chronic lung disease in deployed military personnel

Military personnel are a unique group of individuals referred to the pulmonary physician for evaluation. Despite accession standards that limit entrance into the military for individuals with various pre-existing lung diseases, the most common disorders found in the general population such as asthma and chronic obstructive pulmonary disease remain frequently diagnosed. Military personnel generally tend to be a more physically fit population who are required to exercise on a regular basis and as such may have earlier presentations of disease than their civilian counterparts. Exertional dyspnea is a common complaint; establishing a diagnosis may be challenging given the subtle nature of symptoms and lack of specificity with pulmonary function testing. The conflicts over the past 10 years in Iraq and Afghanistan have also given rise to new challenges for deployed military. Various respiratory hazards in the deployed environment include suspended geologic dusts, burn pits, vehicle exhaust emissions, industrial air pollution, and isolated exposure incidents and may give rise to both acute respiratory symptoms and chronic lung disease. In the evaluation of deployed military personnel, establishing the presence of actual pulmonary disease and the relationship of existing disease to deployment is an ongoing issue to both military and civilian physicians. This paper reviews the current evidence for chronic lung disease in the deployed military population and addresses any differences in diagnosis and management.

Longitudinal changes in response to a cycle-run field test of young male national "talent identification" and senior elite triathlon squads

This study investigated the changes in cardiorespiratory response and running performance of 9 male "Talent Identification" (TID) and 6 male Senior Elite (SE) Spanish National Squad triathletes during a specific cycle-run (C-R) test. The TID and SE triathletes (initial age 15.2 ± 0.7 vs. 23.8 ± 5.6 years, p = 0.03; V(O2)max 77.0 ± 5.6 vs. 77.8 ± 3.6 ml · kg(-1) · min(-1), nonsignificant) underwent 3 tests through the competitive period and the preparatory period, respectively, of 2 consecutive seasons: test 1 was an incremental cycle test to determine the ventilatory threshold (Th(vent)); test 2 (C-R) was 30-minute constant load cycling at the Th(vent) power output followed by a 3-km time-trial run; and test 3 (isolated control run [R]) was an isolated 3-km time-trial control run, in randomized counterbalanced order. In both seasons, the time required to complete the C-R 3-km run was greater than for R in TID (11:09 ± 00:24 vs. 10:45 ± 00:16 min:ss, p < 0.01 and 10:24 ± 00:22 vs. 10:04 ± 00:14, p = 0.006, for season 2005-2006 and 2006-2007, respectively) and SE (10:15 ± 00:19 vs. 09:45 ± 00:30, p < 0.001 and 09:51 ± 00:26 vs. 09:46 ± 00:06, p = 0.02 for season 2005-2006 and 2006-2007, respectively). Compared with the first season, the completion of the time-trial run was faster in the second season (6.6%, p < 0.01 and 6.4%, p < 0.01, for C-R and R tests, respectively) only in TID. Changes in post cycling run performance were accompanied by changes in pacing strategy, but there were only slight or nonsignificant changes in the cardiorespiratory response. Thus, the negative effect of cycling on performance may persist, independently of the period, over 2 consecutive seasons in TID and SE triathletes; however, improvements over time suggests that monitoring running pacing strategy after cycling may be a useful tool to control performance and training adaptations in TID.

Pacing strategy during the initial phase of the run in triathlon: influence on overall performance

The aim of the present study was to determine the best pacing strategy to adopt during the initial phase of a short distance triathlon run for highly trained triathletes. Ten highly trained male triathletes completed an incremental running test to determine maximal oxygen uptake, a 10-km control run at free pace and three individual time-trial triathlons (1.5-km swimming, 40-km cycling, 10-km running) in a randomised order. Swimming and cycling speeds were imposed as identical to the first triathlon performed and the first run kilometre was done alternatively 5% faster (Tri-Run(+5%)), 5% slower (Tri-Run(-5%)) and 10% slower (Tri-Run(-10%)) than the control run (C-Run). The subjects were instructed to finish the 9 remaining kilometres as quickly as possible at a free self-pace. Tri-Run(-5%) resulted in a significantly faster overall 10-km performance than Tri-Run(+5%) and Tri-Run(-10%) (p < 0.05) but no significant difference was observed with C-Run (p > 0.05) (2,028 +/- 78 s vs. 2,000 +/- 72 s, 2,178 +/- 121 s and 2,087 +/- 88 s, for Tri-Run(-5%), C-Run, Tri-Run(+5%) and Tri-Run(-10%), respectively). Tri-Run(+5%) strategy elicited higher values for oxygen uptake, ventilation, heart rate and blood lactate at the end of the first kilometre than the three other conditions. After 5 and 9.5 km, these values were higher for Tri-Run(-5%) (p < 0.05). The present results showed that the running speed achieved during the cycle-to-run transition is crucial for the improvement of the running phase as a whole. Triathletes would benefit to automate a pace 5% slower than their 10-km control running speed as both 5% faster and 10% slower running speeds over the first kilometre involved weaker overall performances.

Physiological differences between cycling and running: lessons from triathletes

The purpose of this review was to provide a synopsis of the literature concerning the physiological differences between cycling and running. By comparing physiological variables such as maximal oxygen consumption (V O(2max)), anaerobic threshold (AT), heart rate, economy or delta efficiency measured in cycling and running in triathletes, runners or cyclists, this review aims to identify the effects of exercise modality on the underlying mechanisms (ventilatory responses, blood flow, muscle oxidative capacity, peripheral innervation and neuromuscular fatigue) of adaptation. The majority of studies indicate that runners achieve a higher V O(2max) on treadmill whereas cyclists can achieve a V O(2max) value in cycle ergometry similar to that in treadmill running. Hence, V O(2max) is specific to the exercise modality. In addition, the muscles adapt specifically to a given exercise task over a period of time, resulting in an improvement in submaximal physiological variables such as the ventilatory threshold, in some cases without a change in V O(2max). However, this effect is probably larger in cycling than in running. At the same time, skill influencing motor unit recruitment patterns is an important influence on the anaerobic threshold in cycling. Furthermore, it is likely that there is more physiological training transfer from running to cycling than vice versa. In triathletes, there is generally no difference in V O(2max) measured in cycle ergometry and treadmill running. The data concerning the anaerobic threshold in cycling and running in triathletes are conflicting. This is likely to be due to a combination of actual training load and prior training history in each discipline. The mechanisms surrounding the differences in the AT together with V O(2max) in cycling and running are not largely understood but are probably due to the relative adaptation of cardiac output influencing V O(2max) and also the recruitment of muscle mass in combination with the oxidative capacity of this mass influencing the AT. Several other physiological differences between cycling and running are addressed: heart rate is different between the two activities both for maximal and submaximal intensities. The delta efficiency is higher in running. Ventilation is more impaired in cycling than in running. It has also been shown that pedalling cadence affects the metabolic responses during cycling but also during a subsequent running bout. However, the optimal cadence is still debated. Central fatigue and decrease in maximal strength are more important after prolonged exercise in running than in cycling.

Physiological consequences of a high work of breathing during heavy exercise in humans

The healthy respiratory system has a remarkable capacity for meeting the metabolic demands placed upon it during strenuous exercise. For example, in order to regulate alveolar partial pressure of oxygen and carbon dioxide during heavy workloads, a 20-fold increase in alveolar ventilation can occur. The high metabolic costs and subsequent increased work of breathing associated with this ventilatory increase can result in a number of limitations to the healthy respiratory system. Two examples of respiratory system limitations that are associated with a high work of breathing are expiratory flow limitation and exercise-induced diaphragmatic fatigue. Expiratory flow limitation can lead to an inability to increase alveolar ventilation (V (A)) in the face of increasing metabolic demands, resulting in gas exchange impairment and diminished endurance exercise performance. Furthermore, the high ventilatory requirements of endurance athletes and the inherent anatomical differences in females could make these groups more susceptible to expiratory flow limitation. Fatigue of the diaphragm has also been documented after strenuous exercise and may be related to a mechanism which increases sympathetic vasoconstrictor outflow and reduces limb blood flow during prolonged exercise. This competition between the muscles of respiration and locomotion for a limited cardiac output may have dramatic consequences for exercise performance. This brief review summarizes the literature as it pertains to the work of breathing, expiratory flow limitation, and exercise-induced diaphragmatic fatigue in healthy humans.

Effects of the order of running and cycling of similar intensity and duration on pulmonary diffusing capacity in triathletes

To study the pathophysiological mechanisms involved in the decrease of post-triathlon diffusing capacity (DLco), blood rheologic properties (blood viscosity: eta(b); changes in plasma volume: deltaPV) and atrial natriuretic factor (ANF) were assessed in ten triathletes during cycle-run (CR) and run-cycle (RC) trials at a metabolic intensity of 75% of maximal oxygen consumption ( VO(2max)). The DLco was measured before and 10 min after trials. ANF and deltaPV were measured at rest, after the cycle and run of CR and RC trials, and at the end of and 10 min after exercise. RC led to a greater deltaDLco decrease, a lower ANF concentration and a lower deltaPV than did CR, whereas for both CR and RC eta(b) was increased throughout exercise and 10 min after. In addition, after CR the deltaDLco decrease was inversely correlated ( r=-0.764; P<0.01) with deltaPV. The association of decreased plasma volume, increased eta(b), and lower ANF concentrations after RC suggested that lower blood pulmonary volume may have caused the greater decrease in Dlco as compared with CR. The inverse correlation between deltaPV and deltaDLco reinforces the hypothesis that fluid shifts limit the post-exercise DLco decrease after the CR succession in triathletes. Lastly, cycling in the crouched position might increase intra-thoracic pressure, decrease thorax volume due to the forearm position on the handlebars, and weaken peripheral muscular pump efficacy, all of which would limit venous return to the heart, and thus result in low pulmonary blood volume. Compared with cycling, running appeared to induce the opposite effects.

Reproducibility of the cycling time to exhaustion at .VO2peak in highly trained cyclists

The purpose of the present study was to examine, in highly trained cyclists, the reproducibility of cycling time to exhaustion (T(max)) at the power output equal to that attained at peak oxygen uptake (.VO2peak) during a progressive exercise test. Forty-three highly trained male cyclists (M +/- SD; age = 25 +/- 6 yrs; weight = 75 +/- 7 kg; .VO2peak = 64.8 +/- 5.2 ml.kg-1.min-1) performed two T(max) tests one week apart. While the two measures of T(max) were strongly related (r = 0.884; p < 0.001), T(max) from the second test (245 +/- 57 s) was significantly higher than that of the first (237 +/- 57 s; p = 0.047; two-tailed). Within-subject variability in the present study was calculated to be 6 +/- 6%, which was lower than that previously reported for T(max) in sub-elite runners (25%). The mean T(max) was significantly (p < 0.05) related to both the second ventilatory turnpoint (VT(2); r = 0.38) and to .VO2peak (r = 0.34). Despite a relatively low within-subject coefficient of variation, these data demonstrate that the second score in a series of two T(max) tests may be significantly greater than the first. Moreover, the present data show that T(max) in highly trained cyclists is moderately related to VT(2) and .VO2peak.