Those Apples Don’t Taste Like Oranges! Why ‘Equalising’ HIIT and MICT Protocols Does Not Make Sense

First paragraph: We read with interest the recent article by Andreato entitled ‘High-Intensity Interval Training: Methodological Considerations for Interpreting Results and Conducting Research’ [1]. We applaud the author’s call for greater clarity in defining and reporting high-intensity interval training (HIIT) protocols; this is much needed to move the field forward. However, we dispute the author’s principal claim that to avoid bias when comparing HIIT with moderate-intensity continuous training (MICT), it is necessary to ‘equalise’ (match) sessions for energy expenditure (or workload performed, as a proxy for energy expenditure). Upon reading the article, we failed to find any sound justification for this assertion

Effects of a novel neurodynamic tension technique on muscle extensibility and stretch tolerance: a counterbalanced cross-over study

Context:  Neurodynamic tension affects hamstring extensibility and stretch tolerance, and is considered important in hamstring injury management. Neurodynamic tension was postulated to affect segmental muscle extensibility and stretch tolerance, and potentially also demonstrate extra-segmental and contralateral effects.   Objectives:  Assess the effects of a novel sciatic-tibial neurodynamic tension technique, the modified long sit slump (MLSS), on segmental, extra-segmental and contralateral muscle extensibility and stretch tolerance.  Study design:  Counterbalanced cross-over study.  Setting:  University research laboratory.  Participants:  Thirteen healthy and active subjects (mean±SD age 24±8 y, BMI 23.1±2.8 kg·m-2).  Intervention:  MLSS application (5 seconds, 5 repetitions, 3 sets) on two occasions with a three-week washout period, and either stance or skill leg treated in a counterbalanced manner.  Main outcome measures:  Segmental and extra-segmental muscle extensibility were measured utilising passive straight leg raise (PSLR) and prone knee bend (PKB) at pre-, immediately post- and one hour post-intervention. Stretch intensity ratings were measured utilising a simple numerical rating scale (SNRS).  Results:  MLSS significantly increased PSLR and PKB bilaterally (

Less pain, more gain – improving health and fitness with minimal exercise

First paragraph: When it comes to exercise, if there was a way to get more health benefits by doing less, then it’s likely a lot of people would be interested. This is probably the reason that high-intensity interval training (HIIT) gets a lot of attention. HIIT can improve health and fitness, but with much less time spent exercising. Much less time when compared with much lower intensity aerobic exercise, that is. Access this article on The Conversation website: https://theconversation.com/less-pain-more-gain-improving-health-and-fitness-with-minimal-exercise-7102

The effect of low volume sprint interval training in patients with non-alcoholic fatty liver disease

Objectives: Exercise is an important part of disease management in patients with non-alcoholic fatty liver disease (NAFLD), but adherence to current exercise recommendations is poor. Novel low-volume sprint interval training (SIT) protocols with total training time commitments of ≤30 min per week have been shown to improve cardiometabolic risk and functional capacity in healthy sedentary participants, but the efficacy of such protocols in the management of NAFLD remains unknown. The aim of the present study was to examine whether a low-volume SIT protocol can be used to improve liver function, insulin resistance, body composition, physical fitness, cognitive function and general well-being in patients with NAFLD.Methods: In the present study, 7 men and 2 women with NAFLD (age: 45±8 y, BMI: 28.7±4.1 kg·m−2) completed a 6-week control period followed by 6 weeks of twice-weekly SIT sessions (5-10×6-s ‘all-out’ cycle sprints). Body composition, blood pressure, liver function, metabolic function, functional capacity, cognitive function and quality of life were assessed at baseline, following the control period, and following the SIT intervention.Results: Walking speed during the walk test (+12%), estimated V̇O2max (+8%), verbal fluency (+44%), and blood platelet count (+12%; all p<0.05) significantly increased during the control period. These measures remained significantly raised compared to baseline following the SIT intervention, but did not significantly change any further compared to the post-control time-point. Diastolic blood pressure decreased from 87±10 to 77±8 mm Hg from the end of the control period to the end of the SIT intervention (p<0.05).Conclusion: This study does not support the use of 6 weeks of a low volume SIT protocol involving twice-weekly sessions with 5-10×6-s ‘all-out’ cycle sprints as an intervention for NAFLD disease management

VO₂max: the gold standard for measuring fitness explained

First paragraph: If you could pick one measure to evaluate your health, what would you pick? Blood pressure? Cholesterol? These are commonly measured by your GP, but there is something that is more informative: maximal aerobic capacity, otherwise known as VO₂max. This measure tells you your maximum (max) rate (V) of oxygen (O₂) uptake and use during exercise. The greater this is, the better your health. In fact, VO₂max is the best predictor of your risk, at a given point in time, of getting chronic diseases like heart disease, type 2 diabetes or certain cancers, and the best predictor of your chances of living a long and healthy life. Intuitively, this does not make much sense: most people go through life without ever needing to reach their VO₂max.https://theconversation.com/vo-max-the-gold-standard-for-measuring-fitness-explained-10948

Effect of Number of Sprints in a SIT Session on Change in VO2max: A Meta-analysis

Purpose:  Recent meta-analyses indicate that sprint interval training (SIT) improves cardiorespiratory fitness (V˙O2max), but the effects of various training parameters on the magnitude of the improvement remain unknown. The present meta-analysis examined the modifying effect of the number of sprint repetitions in an SIT session on improvements in V˙O2max  Methods:  The databases PubMed and Web of Science were searched for original studies that have examined pre- and posttraining V˙O2max in adults after ≥2 wk of training consisting of repeated (≥2) Wingate-type cycle sprints, published up to May 1, 2016. Articles were excluded if they were not in English; if they involved patients, athletes, or participants with a mean baseline V˙O2max of >55 mL·kg−1·min−1 or a mean age <18 yr; and if an SIT trial was combined with another intervention or used intervals shorter than 10 s. A total of 38 SIT trials from 34 studies were included in the meta-analysis. Probabilistic magnitude-based inferences were made to interpret the outcome of the analysis.  Results:  The meta-analysis revealed a likely large effect of a typical SIT intervention on V˙O2max (mean ± 90% confidence limits = 7.8% ± 4.0%) with a possibly small modifying effect of the maximum number of sprint repetitions in a training session (−1.2% ± 0.8% decrease per two additional sprint repetitions). Apart from possibly small effects of baseline V˙O2max and age, all other modifying effects were unclear or trivial. Conclusion:  We conclude that the improvement in V˙O2max with SIT is not attenuated with fewer sprint repetitions, and possibly even enhanced. This means that SIT protocols can be made more time efficient, which may help SIT to be developed into a viable strategy to impact public health

No effect of acute and chronic supramaximal exercise on circulating levels of the myokine SPARC

Myokines may play a role in the health benefits of regular physical activity. Secreted protein acidic rich in cysteine (SPARC) is a pleiotropic myokine that has been shown to be released into the bloodstream by skeletal muscle in response to aerobic exercise. As there is evidence suggesting that SPARC release may be linked to glycogen breakdown and activation of 5’ adenosine monophosphate-activated protein kinase, we hypothesised that brief supramaximal exercise may also be associated with increased serum SPARC levels. In the present study, 10 participants (3 women; mean ± SD age: 21 ± 3 y, body mass index (BMI): 22 ± 3 kg m−2, and V˙O2max: 39 ± 6 mL kg−1 min−1) performed an acute bout of supramaximal cycle exercise (20-s Wingate sprint against 7.5% of body mass, with a 1-min warm-up and a 3-min cool-down consisting of unloaded cycling). Serum SPARC levels were determined pre-exercise as well as 0, 15, and 60 min post-exercise and corrected for plasma volume change. To determine whether regular exercise affected the acute SPARC response, participants repeated the acute exercise protocol three times per week for four weeks, and serum SPARC response to supramaximal exercise was reassessed after this period. Acute supramaximal exercise significantly decreased plasma volume (−10%;p < .001), but was not associated with a significant change in serum SPARC levels at either the pre-training or post-training testing sessions. In conclusion, in contrast to aerobic exercise, a single brief supramaximal cycle sprint is not associated with an increase in serum SPARC levels, suggesting that SPARC release is not related to skeletal muscle glycogen breakdown

Heterogeneity and incidence of non-response for changes in cardiorespiratory fitness following time-efficient sprint interval exercise training

Interindividual variability for training-induced changes in maximal oxygen uptake (VO2max) is well described following continuous aerobic and high-intensity interval training. Whether similar variability is observed following time-efficient sprint interval training with minimal training volume (i.e., reduced-exertion high-intensity interval training; REHIT) is unknown. We conducted a pooled analysis of n=117 (68 men) training participants (mean±SD: age: 30±10 y; VO2max: 34.8±7.5 ml·kg-1·min-1), who completed a VO2max assessment before and 3 days after 6 weeks of REHIT comprising of two 10-20 second ‘all-out’ cycling sprints per session, and n=40 no-intervention control participants (age: 30±13 y; VO2max: 31.5±6.5 ml·kg-1·min-1) who completed repeated VO2max tests over a comparable timeframe. Individual responses estimated using 50% confidence intervals derived from the technical error were interpreted against a smallest worthwhile change (SWC) of 1.75 ml·kg-1·min-1. The standard deviation of individual responses was 2.39 ml·kg-1·min-1 demonstrating clinically meaningful heterogeneity in training-induced changes in VO2max following REHIT that exceed the technical, biological and random within-subjects variability of VO2max assessment. The likely (75% probability) non-response rate was 18% (21/117), and 49% (57/117) of individuals demonstrated increases in VO2max likely higher than the SWC. We conclude that the well-described increase in VO2max following REHIT at the group level is subject to substantial variability in magnitude at an individual level. This has important implications for exercise prescription and can be harnessed to elucidate mechanisms of adaptation