Studying placebo effects in model organisms will help us understand them in humans

The placebo effect is widely recognized, but important questions remain, for example whether the capacity to respond to a placebo is an evolved, and potentially ubiquitous trait, or an unpredictable side-effect of another evolved process. Understanding this will determine the degree to which the physiology underlying placebo effects might be manipulated or harnessed to optimize medical treatments. We argue that placebo effects are cases of phenotypic plasticity where once predictable cues are now unpredictable. Importantly, this explains why placebo-like effects are observed in less complex organisms such as worms and flies. Further, this indicates that such species present significant opportunities to test hypotheses that would be ethically or pragmatically impossible in humans. This paradigm also suggests that data informative of human placebo effects pre-exists in studies of model organisms

Is Olympic inspiration associated with fitness and physical activity in English schoolchildren? A repeated cross- sectional comparison before and 18 months after London 2012

Objectives: To compare cardiovascular fitness and physical activity of schoolchildren 18 months after London 2012 according to Olympic ‘inspiration’. Design: A cross-sectional comparison between groups of schoolchildren categorised according to self- reported Olympic inspiration and a repeated cross- sectional comparison using data collected pre-2012. Setting: Schools within a 50 km radius of the Olympic Park, Stratford, London. Participants: 931 students (10.0–15.9-year-olds) attending 6 schools assessed in 2013 and 2014 (18 (range: 14–20) months after London 2012) and 733 students from the same schools assessed in 2008–2009 (42 (range: 38–46) months before London 2012). Primary outcome measures: Self-reported Olympic inspiration; cardiorespiratory fitness (V_ O mL/kg/ 2peak min) assessed using the 20 m shuttle-run and self- reported physical activity. Secondary outcomes measures: Differences in V_ O2peak before and after London 2012. Results: 53% of children reported being inspired to try new sports or activities. Compared with those not inspired by the Games, V_ O2peak was higher in boys (d=0.43) and girls (d=0.27), who continued to participate in activities at 18(14–20) months. This 45% of sample was also more physically active (boys, d=0.23; girls, d=0.38) than those not or only briefly inspired to participate in activities (boys, d=0.24; girls, d=0.21). Compared with pre-2012 values, V_ O2peak was lower post-2012 in boys (d=0.37) and in girls (d=0.38). Conclusions: High levels of inspiration to participate in new activities reported following London 2012 and positive associations with fitness are encouraging. We cannot discount the possibility that inspired participants may have already been fitter and more active pre-2012. These associations must be interpreted in the context of the significant declines in fitness shown by our repeated cross-sectional comparison. Olympic host countries should employ longitudinal monitoring using objectively measured fitness and physical activity to provide evidence of health-related legacy

Community Fitness Center-Based Physical Activity Interventions: A Brief Review

Sedentary lifestyle is associated with cardiovascular and metabolic diseases. A compelling body of evidence demonstrates the amelioration and prevention of such conditions with increased levels of physical activity (PA). Despite this evidence, many public health initiatives aimed at increasing PA have failed to demonstrate clinically relevant effects on public health. It has been hypothesized that the highly controlled environments in which PA and health research is conducted limits its replicability in real-world community settings. This review aimed to evaluate the effectiveness of community fitness center-based interventions on inactivity-related diseases in adults. Data from 11 investigations highlighted 3 factors: 1) a lack of community-based PA studies, 2) a lack of clinically relevant data, and 3) further reliance on self-report and rudimentary measurements. It is concluded that the current laboratory-based evidence for PA and health is to be replicated yet in real-world settings and that rigorous and clinically relevant naturalistic research is required

High Agreement between Laboratory and Field Estimates of Critical Power in Cycling

The purpose of this study was to investigate the level of agreement between laboratory-based estimates of critical power (CP) and results taken from a novel field test. Subjects were fourteen trained cyclists (age 40±7 yrs; body mass 70.2±6.5 kg; V?O2max 3.8±0.5 L · min-1). Laboratory-based CP was estimated from 3 constant work-rate tests at 80%, 100% and 105% of maximal aerobic power (MAP). Field-based CP was estimated from 3 all-out tests performed on an outdoor velodrome over fixed durations of 3, 7 and 12 min. Using the linear work limit (Wlim) vs. time limit (Tlim) relation for the estimation of CP1 values and the inverse time (1/t) vs. power (P) models for the estimation of CP2 values, field-based CP1 and CP2 values did not significantly differ from laboratory-based values (234±24.4 W vs. 234±25.5 W (CP1); P<0.001; limits of agreement [LOA], -10.98-10.8 W and 236±29.1 W vs. 235±24.1 W (CP2); P<0.001; [LOA], -13.88-17.3 W. Mean prediction errors for laboratory and field estimates were 2.2% (CP) and 27% (W'). Data suggest that employing all-out field tests lasting 3, 7 and 12 min has potential utility in the estimation of CP

Validity and reliability of critical power field testing

PURPOSE To test the validity and reliability of field critical power (CP). METHOD Laboratory CP tests comprised three exhaustive trials at intensities of 80, 100 and 105 % maximal aerobic power and CP results were compared with those determined from the field. Experiment 1: cyclists performed three CP field tests which comprised maximal efforts of 12, 7 and 3 min with a 30 min recovery between efforts. Experiment 2: cyclists performed 3 × 3, 3 × 7 and 3 × 12 min individual maximal efforts in a randomised order in the field. Experiment 3: the highest 3, 7 and 12 min power outputs were extracted from field training and racing data. RESULTS Standard error of the estimate of CP was 4.5, 5.8 and 5.2 % for experiments 1-3, respectively. Limits of agreement for CP were -26 to 29, 26 to 53 and -34 to 44 W for experiments 1-3, respectively. Mean coefficient of variation in field CP was 2.4, 6.5 and 3.5 % for experiments 1-3, respectively. Intraclass correlation coefficients of the three repeated trials for CP were 0.99, 0.96 and 0.99 for experiments 1-3, respectively. CONCLUSIONS Results suggest field-testing using the different protocols from this research study, produce both valid and reliable CP values

Programming and supervision of resistance training leads to positive effects on strength and body composition: results from two randomised trials of community fitness programmes

Background: Many sedentary adults have high body fat along with low fitness, strength, and lean body mass (LBM) which are associated with poor health independently of body mass. Physical activity can aid in prevention, management, and treatment of numerous chronic conditions. The potential efficacy of resistance training (RT) in modifying risk factors for cardiovascular and metabolic disease is clear. However, RT is under researched in public health. We report community-based studies of RT in sedentary (Study 1), and overweight and pre-diabetic (Study 2) populations. Trial Design: Study 1: A semi-randomised trial design. Study 2: A randomised wait-list controlled trial. Methods: Study 1 (48-weeks): Participants choosing either a fitness centre approach, and randomised to structured-exercise (STRUC, n=107), or free/unstructured gym use (FREE, n=110), or not, and randomised to physical-activity-counselling (PAC, n=71) or a measurement only comparator (CONT, n=76). Study 2 (12-weeks): Patients were randomly assigned to; traditional-supervised-exercise (STRUC, n=30), physical-activity-counselling (PAC, n=23), either combined (COMB, n=39), or a wait-list comparator (CONT, n=54). Outcomes for both were BF mass (kg), LBM (kg), BF percentage (%), and strength. Results: Study 1: One-way ANCOVA revealed significant between group effects for BF% and LBM, but not for BF mass or strength. Post hoc paired comparisons revealed significantly greater change in LBM for the STRUC group compared with the CONT group. Within group changes using 95%CIs revealed significant changes only in the STRUC group for both BF% (-4.1 to -0.9%) and LBM (0.1 to 4.5 kg), and in FREE (8.2 to 28.5 kg) and STRUC (5.9 to 26.0 kg) for strength. Study 2: One-way ANCOVA did not reveal significant between group effects for strength, BF%, BF mass, or LBM. For strength, 95%CIs revealed significant within group changes for the STRUC (2.4 to 14.1 kg) and COMB (3.7 to 15.0 kg) groups. Conclusion: Strength increased in both studies across all RT treatments compared to controls, yet significant improvements in both strength and body-composition occurred only in programmed and/or supervised RT. As general increases in physical activity have limited impact upon body-composition, public health practitioners should structure interventions to include progressive RT. Keywords: Resistance Training, Body Composition, Exercise Treatment, Health Status

Changes in insulin sensitivity in response to different modalities of exercise: a review of the evidence

Summary: Type 2 diabetes is an increasingly prevalent condition with complications including blindness and kidney failure. Evidence suggests that type 2 diabetes is associated with a sedentary lifestyle, with physical activity demonstrated to increase glucose uptake and improve glycaemic control. Proposed mechanisms for these effects include the maintenance and improvement of insulin sensitivity via increased glucose transporter type four production. The optimal mode, frequency, intensity and duration of exercise for the improvement of insulin sensitivity are however yet to be identified. We review the evidence from 34 published studies addressing the effects on glycaemic control and insulin sensitivity of aerobic exercise, resistance training and both combined. Effect sizes and confidence intervals are reported for each intervention and meta-analysis presented. The quality of the evidence is tentatively graded, and recommendations for best practice proposed

Modelling of critical power from road data

Background: Performance tests are an integral part of evaluating competitive cyclists. Despite all technological and physiological advances, limited research has been performed addressing the translation of standardized, relevant laboratory tests into the field and consequently into “real world” cycling (i.e. .(i.e. González-Haro et al., 2007: British Journal of Sports Medicine, 41(3), 174–179; Quod et al., 2010:InterInternational Journal of Sports Medicine, 31(6), 397–401; Nimmerichter et al., 2010: International Journal of Sports Medicine, 31(3), 160- 166). For continuous activities between approximately 2 and 30 minutes, the assessment of Critical Power (CP) is one such relevant test. Compromising ecological validity, to date CP testing is mostly constrained to the laboratory. Purpose: To investigate a novel CP road testing protocol. Methods: Laboratory determined CP values using a 30 min intra-trial recovery period (Bishop & Jenkins, 1995: European Journal of Applied Physiology and Occupational Physiology, 72 (1-2), 115-120) were compared with those determined in the field, i.e. on the road. The experiment comprised of planned maximal efforts of 12 min, 7 min and 3 min with a 30 min recovery period between efforts. Linear regression was used to determine CP using the work- Results: There was no significant difference between laboratory and road CP values. The mean difference between the two environments was 0 ± 5.5 W. The standard error of estimates was 1.7% and limits of agreement were -10.8 – 10.8 W (Fig. 1). Discussion: Results suggests that CP can be tested on the road. Gonzales-Haro accepted their incremental velodrome field test as being valid with reported limits of agreement of 130 W to – 24 W and a random error of 13.9%. Our limits of agreement values are considerably higher and standard error of estimate values are considerably lower than those reported by Gonzales-Haro. The experimental protocol provides a practical and easy to use alternative to the conventional testing protocol for coaches and athletes when determining CP in on the road. Conclusion: The aforementioned research provides support for the acceptance of road CP performance testing using a 30 min inter-maximal effort recovery period

Death by effectiveness:Exercise as medicine caught in the efficacy trap!

Sport and Exercise Medicine (SEM) has had a good run. For a while it was the low-cost magic bullet. With efficacy demonstrated in study after study, the conclusion was clear: ‘Exercise is Medicine’, a potential public health panacea. Sadly, the early promise waned. While we continue to be bombarded by original research and reviews extoling the efficacy of exercise, there is an apparent dearth of evidence of its effectiveness. This fact is highlighted in 2014 reports from the UK Government1 and Public Health England.

The 3-min Test Does not Provide a Valid Measure of Critical Power Using the SRM Isokinetic Mode

Recent datas suggest that the mean power over the final 30 s of a 3-min all-out test is equivalent to Critical Power (CP) using the linear ergometer mode. The purpose of the present study was to identify whether this is also true using an "isokinetic mode". 13 cyclists performed: 1) a ramp test; 2) three 3-min all-out trials to establish End Power (EP) and work done above EP (WEP); and 3) 3 constant work rate trials to determine CP and the work done above CP (W') using the work-time (=CP1/W'1) and 1/time (=CP2/W'2) models. Coefficient of variation in EP was 4.45% between trials 1 and 2, and 4.29% between trials 2 and 3. Limits of Agreement for trials 1-2 and trials 2-3 were -2±38 W. Significant differences were observed between EP and CP1 (+37 W, P<0.001), between WEP and W'1(-6.2 kJ, P=0.001), between EP and CP2 (+31 W, P<0.001) and between WEP and W'2 (-4.2 kJ, P=0.006). Average SEE values for EP-CP1 and EP-CP2 of 7.1% and 6.6% respectively were identified. Data suggest that using an isokinetic mode 3-min all-out test, while yielding a reliable measure of EP, does not provide a valid measure of CP