Multi-Stage 20-m Shuttle Run Fitness Test, Maximal Oxygen Uptake and Velocity at Maximal Oxygen Uptake.

The multi-stage 20-m shuttle run fitness test (20mMSFT) is a popular field test which is widely used to measure aerobic fitness by predicting maximum oxygen uptake (VO2max) and performance. However, the velocity at which VO2max occurs (vVO2max) is a better indicator of performance than VO2max, and can be used to explain inter-individual differences in performance that VO2max cannot. It has been reported as a better predictor for running performance and it can be used to monitor athletes' training for predicting optimal training intensity. This study investigated the validity and suitability of predicting VO2max and vVO2max of adult subjects on the basis of the performance of the 20mMST. Forty eight (25 male and 23 female) physical education students performed, in random order, a laboratory based continuous horizontal treadmill test to determine VO2max, vVO2max and a 20mMST, with an interval of 3 days between each test. The results revealed significant correlations between the number of shuttles in the 20mMSFT and directly determined VO2max (r = 0.87, p<0.05) and vVO2max (r = 0.93, p<0.05). The equation for prediction of VO2max was y = 0.0276x + 27.504, whereas for vVO2max it was y = 0.0937x + 6.890. It can be concluded that the 20mMSFT can accurately predict VO2max and vVO2max and this field test can provide useful information regarding aerobic fitness of adults. The predicted vVO2max can be used in monitoring athletes, especially in determining optimal training intensity

Barefoot running improves economy at high intensities and peak treadmill velocity

Aim: Barefoot running can improve running economy (RE) compared to shod running at low exercise intensities, but data is lacking for the higher intensities typical during many distance running competitions. The influence of barefoot running on the velocity at maximal oxygen uptake (vVO2max) and peak incremental treadmill test velocity (vmax) is unknown. The present study tested the hypotheses that barefoot running would improve RE, vVO2max and vmax relative to shod running. Methods: Using a balanced within-subject repeated measures design, eight male runners (aged 23.1±4.5 years, height 1.80±0.06 m, mass 73.8±11.5 kg, VO2max 4.08±0.39 L·min-1) completed a familiarization followed by one barefoot and one shod treadmill running trial, 2-14 days apart. Trial sessions consisted of a 5 minute warm-up, 5 minute rest, followed by 4×4 minute stages, at speeds corresponding to ~67, 75, 84 and 91% shod VO2max respectively, separated by a 1 minute rest. After the 4th stage treadmill speed was incremented by 0.1 km·h-1 every 15 s until participants reached volitional exhaustion. Results: RE was improved by 4.4±7.0% across intensities in the barefoot condition (P=0.040). The improvement in RE was related to removed shoe mass (r2=0.80, P=0.003) with an intercept at 0% improvement for RE at 0.520 kg total shoe mass. Both vVO2max (by 4.5±5.0%, P=0.048) and vmax (by 3.9±4.0%, P=0.030) also improved but VO2max was unchanged (p=0.747). Conclusion: Barefoot running improves RE at high exercise intensities and increases vVO2max and vmax, but further research is required to clarify the influence of very light shoe weights on RE

Lung volumes identify an at-risk group in persons with prolonged secondhand tobacco smoke exposure but without overt airflow obstruction.

IntroductionExposure to secondhand smoke (SHS) is associated with occult obstructive lung disease as evident by abnormal airflow indices representing small airway disease despite having preserved spirometry (normal forced expiratory volume in 1 s-to-forced vital capacity ratio, FEV1/FVC). The significance of lung volumes that reflect air trapping in the presence of preserved spirometry is unclear.MethodsTo investigate whether lung volumes representing air trapping could determine susceptibility to respiratory morbidity in people with SHS exposure but without spirometric chronic obstructive pulmonary disease, we examined a cohort of 256 subjects with prolonged occupational SHS exposure and preserved spirometry. We elicited symptom prevalence by structured questionnaires, examined functional capacity (maximum oxygen uptake, VO2max) by exercise testing, and estimated associations of those outcomes with air trapping (plethysmography-measured residual volume-to-total lung capacity ratio, RV/TLC), and progressive air trapping with exertion (increase in fraction of tidal breathing that is flow limited on expiration during exercise (per cent of expiratory flow limitation, %EFL)).ResultsRV/TLC was within the predicted normal limits, but was highly variable spanning 22%±13% and 16%±8% across the increments of FEV1/FVC and FEV1, respectively. Respiratory complaints were prevalent (50.4%) with the most common symptom being ≥2 episodes of cough per year (44.5%). Higher RV/TLC was associated with higher OR of reporting respiratory symptoms (n=256; r2=0.03; p=0.011) and lower VO2max (n=179; r2=0.47; p=0.013), and %EFL was negatively associated with VO2max (n=32; r2=0.40; p=0.017).ConclusionsIn those at risk for obstruction due to SHS exposure but with preserved spirometry, higher RV/TLC identifies a subgroup with increased respiratory symptoms and lower exercise capacity

Prediction of VO\u3csub\u3e2\u3c/sub\u3e Peak Using Sub-Maximum Bench Step Test in Children

The purpose of this study was to develop a valid prediction of maximal oxygen uptake from data collected during a submaximum bench stepping test among children ages 8-12 years. Twentyseven active subjects (16 male and 11 female), weight 36.1 kg, height 144.4 cm and VO2 47.4 ± 7.9 ml/kg/min participated. Subjects completed a maximal oxygen consumption test with analysis of expired air and a submaximal bench stepping test. A formula to predict VO2max was developed from height, resting heart rate and heart rate response during the submaximum bench stepping test. This formula accounted for 71% of the variability in maximal oxygen consumption and is the first step in verifying the validity of the submaximum bench stepping test to predict VO2max. VO2max = -2.354 + (Height in cm * 0.065) + (Resting Heart Rate * 0.008) + (Step Test Average Heart Rate as a Percentage of Resting Heart Rate * -0.870

Cardiorespiratory Fitness Is Inversely Associated With Clustering of Metabolic Syndrome Risk Factors: The Ball State Adult Fitness Program Longitudinal Lifestyle Study

Objective: The focus of this study was the association between the metabolic syndrome (MetSyn) and cardiorespiratory fitness (CRF) defined as maximal oxygen uptake (VO2max). Although previous research has shown a relationship between MetSyn and CRF, most studies are based on less objective measures of CRF and different cardiometabolic risk factor thresholds from earlier guidelines

Non-Aβ-dependent factors associated with global cognitive and physical function in alzheimer's disease: a pilot multivariate analysis

Recent literature highlights the importance of identifying factors associated with mild cognitive impairment (MCI) and Alzheimer's Disease (AD). Actual validated biomarkers include neuroimaging and cerebrospinal fluid assessments; however, we investigated non-Aβ-dependent factors associated with dementia in 12 MCI and 30 AD patients. Patients were assessed for global cognitive function (Mini-Mental state examination-MMSE), physical function (Physical Performance Test-PPT), exercise capacity (6-min walking test-6MWT), maximal oxygen uptake (VO₂max), brain volume, vascular function (flow-mediated dilation-FMD), inflammatory status (tumor necrosis factor-α ,TNF- α, interleukin-6, -10 and -15) and neurotrophin receptors (p75NTR and Tropomyosin receptor kinase A -TrkA). Baseline multifactorial information was submitted to two separate backward stepwise regression analyses to identify the variables associated with cognitive and physical decline in demented patients. A multivariate regression was then applied to verify the stepwise regression. The results indicated that the combination of 6MWT and VO₂max was associated with both global cognitive and physical function (MMSE = 11.384 + (0.00599 × 6MWT) - (0.235 × VO₂max)); (PPT = 1.848 + (0.0264 × 6MWT) + (19.693 × VO₂max)). These results may offer important information that might help to identify specific targets for therapeutic strategies (NIH Clinical trial identification number NCT03034746)

The Effects of Kettlebell Training on Aerobic Capacity

The purpose of this study was to determine the effects of a kettlebell training program on aerobic capacity. Seventeen female NCAA Division I collegiate soccer players (age 19.7 +1.0 years, height 166.1 +6.4 cm, weight 64.2 +8.2 kg) completed a graded exercise test to determine maximal oxygen consumption (VO2max). Participants were placed into a kettlebell intervention (KB) group (n = 9) or a circuit weight training control (CWT) group (n = 8). Participants in the KB group completed a kettlebell snatch test to determine individual snatch repetitions. Both groups trained 3 days per week for 4 weeks in addition to their off-season strength and conditioning program. The KB group performed the 15:15 MVO2 protocol (20 min of kettlebell snatching with a 15 s work-to- rest ratio). The CWT group performed multiple free weight and dynamic body weight exercises as part of a continuous circuit program for 20 min. The 15:15 MVO2 protocol significantly increased VO2max in the KB group. The average increase was 2.3 ml*kg*-1min-1, or approximately a 6% gain. There was no significant change in VO2max in the CWT control group. Thus, the 4-week 15:15 MVO2 kettlebell protocol, using high intensity kettlebell snatches, significantly improved aerobic capacity in female intercollegiate soccer players

Mechanisms of exercise-induced improvements in the contractile apparatus of the mammalian myocardium

One of the main outcomes of aerobic endurance exercise training is the improved maximal oxygen uptake, and this is pivotal to the improved work capacity that follows the exercise training. Improved maximal oxygen uptake in turn is at least partly achieved because exercise training increases the ability of the myocardium to produce a greater cardiac output. In healthy subjects, this has been demonstrated repeatedly over many decades. It has recently emerged that this scenario may also be true under conditions of an initial myocardial dysfunction. For instance, myocardial improvements may still be observed after exercise training in post-myocardial infarction heart failure. In both health and disease, it is the changes that occur in the individual cardiomyocytes with respect to their ability to contract that by and large drive the exercise training-induced adaptation to the heart. Here, we review the evidence and the mechanisms by which exercise training induces beneficial changes in the mammalian myocardium, as obtained by means of experimental and clinical studies, and argue that these changes ultimately alter the function of the whole heart and contribute to the changes in whole-body function

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

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 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