Relationship between VO(2max) and repeated sprint ability using non-motorised treadmill ergometry.

AIM: The aim of this study was to investigate the relationship between maximal oxygen uptake (Vo(2max)) and repeated sprint ability (RSA) using non-motorised treadmill ergometry. METHODS: Ten male participants (mean [standard deviation] VO(2max): 57.5 [2.1] mL x kg(-1).min(-1)) completed a RSA test (10, 6-s sprints with 34-s recovery) on a non-motorised treadmill. Oxygen consumption (VO(2)) and heart rate (HR) were measured during the RSA test and the decrement of performance fatigue (%(d)) was calculated for the performance indices mean maximal speed (MxSp) and average power output (AvPO). RESULTS: There were significant relationships between VO(2max) and the %(d) MxSp (r=-0.75, P<0.05) and VO(2max) and the %(d) AvPO (r=-0.69, P<0.05). There were also significant relationships between VO(2max) and HR recovery (r=0.56, P<0.05) and VO(2max) and VO(2) recovery (r=0.7, P<0.01). However, while no significant relationships were reported between HR recovery and %(d) MxSp (r= 0.45, P>0.05) and HR recovery and %(d) AvPO (r=-0.52, P>0.05), significant relationships were observed between VO(2) recovery and %(d) MxSp (r=-0.75, P<0.05) and between VO(2) recovery and %(d) AvPO (r=-0.77, P<0.05). CONCLUSION: The findings of this study suggest that VO(2max) may be an important factor determining RSA during repeated, high-intensity running-based exercise, such as field hockey, rugby and soccer.

Reliability of repeated sprint exercise in non-motorised treadmill ergometry.

Although repeated sprint tests are relatively common, there have been few investigations of repeated sprint exercise using non-motorised treadmill ergometry. The purpose of this study was to determine the reliability of a repeated sprint procedure using this apparatus. Ten healthy, active males, performed three repeated sprint tests (six repetitions of 6 s sprints with 30 s recovery) on three separate occasions. Performance as determined by maximal speed, average force production, and fatigue were compared across the three trials. Maximal speed and average force were not significantly different between visits (p < 0.05) and a variety of reliability measures suggested good agreement (e.g., coefficient of variations no more than 5 %). The fatigue indices for maximal speed and for average force were generally less reliable (coefficients of variation around 30 % in both cases). In conclusion, measures of performance (maximal speed and average force) can provide reliable results in a repeated sprint protocol but the reliability of fatigue measures appears to be low.

The repeatability and criterion related validity of the 20 m multistage fitness test as a predictor of maximal oxygen uptake in active young men.

OBJECTIVE: To investigate the repeatability and criterion related validity of the 20 m multistage fitness test (MFT) for predicting maximal oxygen uptake (Vo(2max)) in active young men. METHODS: Data were gathered from two phases using 30 subjects (x+/-s; age = 21.8+/-3.6 years, mass = 76.9+/-10.7 kg, stature = 1.76+/-0.05 m). MFT repeatability was investigated in phase 1 where 21 subjects performed the test twice. The MFT criterion validity to predict Vo(2max) was investigated in phase 2 where 30 subjects performed a continuous incremental laboratory test to volitional exhaustion to determine Vo(2max) and the MFT. RESULTS: Phase 1 showed non-significant bias between the two applications of the MFT (x(diff)+/-s(diff) = -0.4+/-1.4 ml kg(-1) min(-1); t = -1.37, p = 0.190) with 95% limits of agreement (LoA) +/-2.7 ml kg(-1) min(-1) and heteroscedasticity 0.223 (p = 0.330). Log transformation of these data reduced heteroscedasticity to 0.056 (p = 0.808) with bias -0.007+/-0.025 (t = -1.35, p = 0.190) and LoA+/-0.049. Antilogs gave a mean bias on the ratio scale of 0.993 and random error (ratio limits) x/divided by 1.050. Phase 2 showed that the MFT significantly underpredicted Vo(2max) (x(diff)+/-s(diff) = 1.8+/-3.2 ml kg(-1) min(-1); t = 3.10, p = 0.004). LoA were +/-6.3 ml kg(-1) min(-1) and heteroscedasticity 0.084 (p = 0.658). Log transformation reduced heteroscedasticity to -0.045 (p = 0.814) with LoA+/-0.110. The significant systematic bias was not eliminated (x(diff)+/-s(diff) = 0.033+/-0.056; t = 3.20, p = 0.003). Antilogs gave a mean bias of 1.034 with random error x/divided by 1.116. CONCLUSIONS: These findings lend support to previous investigations of the MFT by identifying that in the population assessed it provides results that are repeatable but it routinely underestimates Vo(2max) when compared to laboratory determinations. Unlike previous findings, however, these results show that when applying an arguably more appropriate analysis method, the MFT does not provide valid predictions of Vo(2max).

Reliability of power output measurements during repeated treadmill sprinting in rugby players.

The non-motorized treadmill system initially reported by Lakomy in 1984 has been used extensively to assess sprinting performance. However, there has been limited research into the reliability of power output measurement using such systems. The aim of this study was to design a system and protocol capable of measuring treadmill sprinting performance in rugby players and to assess the reliability of this system for measuring power output. Twenty-seven rugby players, all of whom were familiar with treadmill sprinting, performed three maximal 6 s sprints with 2 min recovery between sprints, on two occasions 1 week apart. Both tests were performed on a non-motorized Woodway tramp treadmill, interfaced to a data acquisition system. There were no significant differences (P > 0.05) between power output for repeated trials on the same day (between trials) or for repeated trials on different days (between days). Limits of agreement for maximum average power (the average of 100 readings per second) were 4+/-98 and 30+/-157 W for between trials and between days, respectively. When reported as ratio limits of agreement, these were 1.07 (*/divided 1.12) and 1.03 (*/divided 1.16), respectively. The limits of agreement for maximum instantaneous power (the highest of 100 readings per second) were 51+/-464 and 105+/-588 W for between trials and between days, respectively. When reported as ratio limits of agreement, these were 1.02 (*/divided 1.20) and 1.04 (*/divided 1.21) for between trials and between days, respectively. The coefficients of variation for all measures of power output were less than 9.3%. Hence, the treadmill system and protocol developed in this study provide a reliable measure of power output for rugby players.

A 1-day maximal lactate steady-state assessment protocol for trained runners.

PURPOSE: Identification of the maximal lactate steady state (MLSS) involves multiple days of testing. Heart rate (HR), rating of perceived exertion (RPE), breathing frequency (bf), and race pace may be useful in estimating the MLSS, thus allowing for testing to occur in a single day. The purpose of this investigation was to design a single-session protocol for determining MLSS using HR, RPE, bf, and race pace as predictors. METHODS: Twelve endurance athletes (mean +/- SD, VO2max 64.6 +/- 7.8 mL x kg(-1) x min(-1)) performed the MLSS protocol run and two 27-min validation runs on a treadmill. Running velocity at 87% HRmax RPE of 12, bf of 32 breaths x min(-1), and race pace were used as a starting point for testing. Blood was collected every 3 min of each 9-min stage of the protocol run and analyzed for lactate (La) concentration. The velocity associated with the MLSS was determined as the average of the stage of La steady state and the stage of La accumulation. Validation runs were performed at a velocity 7.5 m x min(-1) below and 7.5 m x min(-1) above the protocol-determined MLSS. If the slower run exhibited a La steady state and the faster run an accumulation of La, then the protocol-determined MLSS value was considered valid. RESULTS: The protocol run was successful in predicting the MLSS in 9 out of 12 subjects (P < or = 0.05). CONCLUSIONS: The proposed protocol employing HR, RPE, bf, and race pace as a starting point for testing can be used to identify the MLSS in one testing session.