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Todora_marc-Lactate-update

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Todora_marc-Lactate-update

  1. 1. Blood Lactate Levels and the Effects of Recovery Methods on Repeated Sprint Performance Joe Todora, Brandon Augustine, Nate Jendrzejewski, Zack Price, Ben Smith Faculty Sponsor (s): Dr. Sally Paulson, Dr. William Braun Department of Exercise Science Abstract A drop in muscle pH associated with lactate accumulation during short-term, high-intensity exercise may be a cause for local muscle fatigue. Lactate removal occurs naturally within the body; however, it is unclear if certain recovery modalities might be used to enhance lactate clearance and subsequent performance. PURPOSE: To examine the difference in effects of cold water immersion (CWI), active recovery (AR), and passive recovery (CON) on blood lactate levels after successive bouts of sprinting. METHODS: Eight active healthy male university students participated in this study. The subjects had a mean age of 21.5 ± 1.31 years, mean mass of 81.25 ± 15.39 kg, and mean height of 181.45 ± 9.68 cm. Resting measurements for blood lactate and heart rate (HR) were taken after 10 minutes of seated rest. Subjects then performed a 400m sprint at maximal effort. HR and blood lactate were then recorded again. Each subject was required to test three different days, each day consisting of a random recovery modality. HR was taken every five minutes during each 20 minute recovery period. Blood lactate was taken within three minutes after the recovery period and after a 35 minute rest period for all three conditions. Subjects completed a 200 m sprint and HR and lactate were taken upon completion. A two-way ANOVA with repeated measures was used to determine any significant differences in blood lactate or HR between the three recovery modalities. A one-way ANOVA with repeated measures was used to determine any significant difference in sprint performance times after each recovery method. RESULTS: There was no significant difference shown between the recovery modalities on all 3 variables: lactate (p = .21), HR (p = .70), and 200 m performance time (CON: 32.13±1.34 s; AR: 33.56±1.95 s; and CWI: 32.91±1.75 s) (p = .30). CONCLUSION: The results of this study do not support an advantage for blood lactate clearance or an impact on 200 m sprint performance time between the three recovery modalities. Introduction For short-term, high intensity exercise, the body relies on rapid production of Adenosine Triphosphate (ATP). ATP is produced naturally in the body through several pathways, including glycolysis. During short-term, high intensity exercise, aerobic metabolism cannot fulfill the ATP turnover demand. As a result, glycolysis predominates, producing excess lactate. Increased lactate accumulation is associated with a painful discomfort in the muscles, and lowers the pH of the blood. As the blood becomes acidic, enzymatic function is negatively affected, slowing down glycolysis and ATP production. With reduced ATP, the muscles fatigue quickly during sustained high-intensity exercise. There are many recovery methods that can be utilized to help clear blood lactate. Results of previous studies suggest that low-intensity exercise is more effective in the clearance of blood lactate than passive rest or moderate-intensity exercise (Ferreira et. al 2011, Menzies et. al 2010). Cold water immersion has been examined as a possible recovery method as well, but results show inconclusive benefits for lactate clearance (Sayers et. al 2001; Vaille et. al 2011). The purpose of this research was to examine the effects of active recovery (AR), cold water immersion (CWI), and passive rest (CON) on lactate clearance, HR, and repeated sprint performance. We hypothesized that AR would provide the most efficient lactate clearance and CWI would result in better performance times in subsequent testing. Methods • Subjects (Table 1) sat for 10 minutes upon arrival. Blood Lactate and resting HR were collected 3 minutes prior to the warm up. • After 10 minutes of rest subjects warmed up on a cycle ergometer at 60 rpm for 5 minutes with no resistance. • Subjects then completed 400-m dash with HR and blood lactate measured immediately upon completion. • Subjects then completed assigned recovery method for 20 minutes: (CON = Seated rest; AR = leg ergometry at 40 rpm; CWI = Water immersion). • HR was measured every 5 minutes during selected recovery method. • After completion of recovery method blood lactate was measured. • Upon completion of recovery method the test subject then rested for 35 minutes. • Prior to the 200-m dash, subjects warmed up the on cycle ergometer for 5 minutes at 60rpm with no resistance. • Blood lactate and HR were collected upon completion of the warm up and before the 200-m dash. • Subjects completed the 200-m dash. • Blood lactate and HR were collected immediately after 200-m dash. Results Figure 1 shows the mean lactate measurements for eight subjects during the testing protocol for the three different recovery methods. There was a statistical trend for differences in lactate between time and recovery conditions (p = .083). There was a statistically significant effect on blood lactate over time for the recovery conditions (p <0.05). Recovery method provided no statistically significant effect on blood lactate (p = .25). Figure 2 shows the mean HR measurements for eight subjects during the testing protocol for the three different recovery methods. There was no statistically significant difference in HR between time and recovery condition as well as recovery conditions on heart rate respectively (p = .09; p = .70). Time had a statistically significant effect on heart rate (p = .00). Figure 3 shows mean performance times for the 200m sprint following each of the three recovery conditions. Mean and standard deviation for the 200m performance times were; CON 32.13±1.34, AR 33.56±1.95, and CWI 32.91±1.75 sec (Figure 3). There was no statistically significant difference in 200m performance times across the three different recovery conditions (p = .30). Discussion The results of this study show that there is no statistically significant difference between CON, AR and CWI for lactate clearance or subsequent sprint performance. The results indicate that recreationally active male undergraduate students did not clear blood lactate faster or have faster 200m performance times based on any of the three different recovery modalities. Although we did not find statistically significant data in clearing blood lactate, there was a trend seen in blood lactate clearance. CWI and AR produced the lowest mean blood lactate measures after the recovery period (~35% lower than CON). However, these differences were non-significant. It is recommend that a larger population of subjects be assessed for clearance of blood lactate after repeated sprint measures. This is important for future research in blood lactate clearance because of the trend found in active recovery compared to passive recovery. Given the trends, it is conceivable that a meaningful difference may be found for blood lactate clearance across the different recovery modalities if the subject pool was expanded. Applying additional sprints could also help tease apart trends seen in the results. References Ferreira, J., R. Carvalho, T. Barroso, L. Szmuchrowski, D. Sledziewski. 2011. Effect of different types of recovery on blood lactate removal after maximum exercise. Political Journal of Sport Tourism 18: 105-111. Menzies, P., C. Menzies, L. Mcintyre, P. Paterson, J. Wilson, and O.J. Kemi. 2010. Blood lactate clearance during active recovery after an intense running bout depends on the intensity of the active recovery. Journal of Sports Sciences 28(9): 975-982 Sayers, M.G., A. M. Calder, and J. G. Sanders. 2011. Effects of whole-body contrast-water therapy on recovery from intense exercise of short duration. European Journal of Sport Science 11 (4): 293-302 Vaile, J., C. O’Hagan, B. Stefanovic, M. Walker, N. Gill, and C.D. Askew. 2011. Effect of cold water immersion on repeated cycling performance and limb blood flow. British Journal of Sports Medicine 45: 825-829 Supported by Shippensburg University-UGR grant #2014/2015-30. Table 1. Subject Descriptive Characteristics (N=8) Figure 3. Mean performance times for the 200m following the control recovery group (CON), active recovery (AR), and cold water immersion (CWI). Descriptive M SD Age (yrs.) 21.5 1.31 Mass (kg) 81.25 15.39 Height (cm) 181.45 9.68 BMI (kg/m2) 24.56 3.31 Body Fat (%) 13.71 4.54 0 2 4 6 8 10 12 14 Pre-400m Post-400m Post Recovery Pre-200m Post-200m Lactate(mmol/L) Time CON AR CWI 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 Resting HR Pre-400m HR Post 400m HR 5 min Recovery HR 10 min Recovery HR 15 min Recovery HR 20 min Revovery HR Pre 200m HR Post 200m HR HeartRate(BPM) Time Con AR CWI 20 22 24 26 28 30 32 34 36 CON AR CWI Time(s) Recovery Groups Figure 2. Mean heart rate (HR) measurements for eight subjects during the testing protocol with a recovery period that consisted of a control group (CON), active recovery (AR), and cold water immersion (CWI). Figure 1. Mean lactate measurements for eight subjects during the testing protocol with a recovery period that consisted of a control group (CON), active recovery (AR), and cold water immersion (CWI). All time points differ except post-400m and post-200m.

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