The Effects and Differences of Sprint Interval Training, Endurance Training and the Training Types Combined on Physiological Parameters and Exercise Performance

Abstract

Sprint Interval Training (SIT) is a time efficient way in order to elicit similar changes as Endurance Training (ET) on aerobic capacity, with the purpose of the exercise training to alter physiological systems and exceed resting homeostasis to improve and enhance physical work capacity (Hawley et al., 1997), ultimately achieving the most out of each training session, beneficial for health and performance. Research in the area has demonstrated, the positive effects of SIT and ET on some physiological, performance and health parameters, with further needed to establish these adaptations. Yet no research is currently available combining these two training types, in a single training session to obtained potentially greater benefits over the same period of time. The aim of this study was to compare and contrast the effects of SIT, ET and COMB training modalities on physiological parameters and exercise performance after an 8 week training programme. Twenty nine participants volunteered to take part in the 10 week matched paired study, which included an 8 week training programme (age; 35.1±13.1 years, female; 16). All participants undertook a preliminary VO2max test and baseline measurements were taken. Participants were then matched paired into groups, based on sex, VO2peak (ml/kg/min) and resting heart rate (HR), then randomly assigned into a sprint interval (SIT), endurance (ET), a combined (COMB) sprint interval and endurance group or control group (CON). Participants in the SIT group undertook; 5-8 repetitions of 5-second sprints over the 8 weeks, on a cycle ergometer with intervals of 30 seconds, twice, interspaced with 4 minutes rest (<50rpm) three times per week. Those assigned to the ET group carried out cycling for 40 increasing to 60 minutes over the 8 weeks, at 60% of VO2peak equivalent to 78.5% of maximum HR, three times per week. The COMB group undertook combination of the above two protocols based on the pilot study undertaken. The CON group were not required to undertake any training regime. After 4 week and 8 weeks of the training, all participants were required to undertake a VO2max test and baseline measures were re-recorded. Prior to each VO2max test, capillary blood samples were taken for the colorimetric assessment of cholesterol. Two way factorial analysis of variance (ANOVA) were used for statistical analysis with lowest standard deviation (LSD) correction to reduce the type 1 error. Repeated measures ANOVA were used to assess changes within each individual training modality. Results indicate that SIT, ET, COMB and CON groups were not significantly different at baseline in VO2max (p=0.993) and Resting HR (p=0.790) after being match paired into groups by these variables. Significant differences were evident in resting HR between the CON and SIT (p=0.005), CON and ET (p=0.016) as well as CON and COMB (0.026) after the 8 weeks of training. Additionally within the training groups in resting HR; SIT (p=0.006), COMB (p=0.016), ET (p=0.036). Significant differences were seen in relative AT between SIT and CON (p=0.097) after 8 weeks, as well as within the COMB group (p=0.028). Furthermore in diastolic blood pressure after 4 weeks between SIT and COMB (p=0.024), COMB and CON (p=0.029) and after 8 weeks between COMB and ET (p=0.032), COMB and SIT (p=0.033) and COMB and CON (p=0.029). In addition, significance was shown in triglycerides after 8 weeks of training, between ET and CON (p=0.032), SIT and COMB (p=0.025) and COMB and CON (p=0.008) CON. Finally significance was evident in blood glucose between COMB and SIT, halfway (p=0.002) and post training (p=0.019). In terms of age, there was a significant difference in VO2max between those aged <35 years and those >35 years in VO2max after 4 (p=0.022) and 8 weeks (p=0.020) of the training programme. Overall the results indicated that when ET is substituted partly with SIT greater beneficial effects are obtained in numerous variables, demonstrated in this study, which has previously established, SIT is a time efficient training method. Furthermore, a lower duration of sprint i.e. 5 seconds, a more feasible sprint duration, as undertaken in this study provided comparable benefits to previous studies who have adopted longer sprint duration. Finally, these findings on various physiological measures and in a range of ages, indicate that a short time frame or by adopting a combined approach to training, can assist with reducing important health and performance parameters such as blood cholesterol, resting HR, blood pressure and ultimately maximal oxygen consumption and exercise performance, key indicators of cardiorespiratory fitness and health.