include an overview of research examining the effectiveness of the FM and identified areas where little research has been conducted. In addition, we describe research involving some of the internal processes through which the FM is thought to effect changes. We refer to this as mechanism of action
Evidence for the Effectiveness of the Feldenkrais Method
James Stephens and Susan Hillier
If It All Comes Down to Bodily Awareness, How Do We Know? Assessing Bodily Awareness
Wolf E. Mehling
It has been suggested that improvement in bodily awareness is a key mechanism of action for many movement therapies ( Mehling et al., 2011 ). Examples of these mind–body therapies include mindful movement, integrative exercise, movement-education approaches named after or by founding teachers (e
Capsaicinoid and Capsinoids as an Ergogenic Aid: A Systematic Review and the Potential Mechanisms Involved
Vilton E.L. de Moura e Silva, Jason M. Cholewa, François Billaut, Ralf Jäger, Marcelo C. de Freitas, Fabio S. Lira, and Fabrício E. Rossi
regarding the effects of CAP on exercise performance. Therefore, the objective of this systematic review was to investigate the effects of CAP compounds as an ergogenic aid and to discuss the underlying mechanisms of action by which these supplements may potentially enhance endurance and resistance exercise
Evidence-Based Supplements for the Enhancement of Athletic Performance
Peter Peeling, Martyn J. Binnie, Paul S.R. Goods, Marc Sim, and Louise M. Burke
in duration. Sodium Bicarbonate Ingestion of sodium bicarbonate (NaHCO 3 ) is proposed to enhance high-intensity exercise performance as an extracellular (blood) buffer; however, the mechanisms of action are complex ( Siegler et al., 2016 ). Although playing an important role in the maintenance of
The Effect of a Prefabricated Foot Orthotic on Frontal Plane Joint Mechanics in Healthy Runners
Thomas G. Almonroeder, Lauren C. Benson, and Kristian M. O’Connor
The mechanism of action of a foot orthotic is poorly understood. The purpose of this study was to use principal components analysis (PCA) to analyze the effects of a prefabricated foot orthotic on frontal plane knee and ankle mechanics during running. Thirty-one healthy subjects performed running trials with and without a foot orthotic and PCA was performed on the knee and ankle joint angles and moments to identify the dominant modes of variation. MANOVAs were conducted on the retained principal components of each waveform and dependent t tests (P < .05) were performed in the case of significance. Mechanics of the ankle were not affected by the foot orthotic. However, mechanics of the knee were significantly altered as subjects demonstrated an increase in the magnitude of the knee abduction moment waveform in an orthotic condition. Subjects also demonstrated a significant shift in the timing of the knee abduction moment waveform toward later in the stance phase in the orthotic condition. These orthotic effects were not related to subject’s foot mobility, measured using the navicular drop test. The mechanism of action of a foot orthotic may be related to their effect on the timing of frontal plane knee loading.
Antioxidants, Carnitine, and Choline as Putative Ergogenic Aids
Mitchell M. Kanter and Melvin H. Williams
Three nutritional products that have very different mechanisms of action are antioxidant vitamins, carnitine, and choline. Antioxidant vitamins do not appear to have a direct effect on physical performance in well-fed people but have been touted for their ability to detoxify potentially damaging free radicals produced during exercise. Carnitine purportedly enhances lipid oxidation, increases VO2max, and decreases plasma lactate accumulation during exercise. However, studies of carnitine do not generally support its use for ergogenic purposes. Choline supplements have been advocated as a means of preventing the decline in acetylcholine production purported to occur during exercise; this decline may reduce the transmission of contraction-generating impulses across the skeletal muscle, an effect that could impair one’s ability to perform muscular work. However, there are no definitive studies in humans that justify choline supplementation. Much of the scientific data regarding the aforementioned nutrients are equivocal and contradictory. Their potential efficacy for improving physical performance remains largely theoretical.
Effects of Caffeine on Repetitions to Failure and Ratings of Perceived Exertion During Resistance Training
J. Matt Green, P. Jason Wickwire, John R. McLester, Shawn Gendle, Geoffrey Hudson, Robert C. Pritchett, and C. Matt Laurent
Ergogenic effects of caffeine on aerobic or endurance exercise are well documented. Conversely, the ergogenic value of caffeine on high-intensity, primarily anaerobic performance is not well understood even though the proposed mechanisms of action for caffeine permit a strong theoretical basis for application to this type of exercise.
This study examined effects of caffeine (Ca) on number repetitions (reps), ratings of perceived exertion (RPE), and peak heart rate (PHR) during resistance-training exercise with reps performed to volitional failure.
Subjects (N = 17) were tested for 10-rep maximum in bench press (BP) and leg press (LP). In sessions 2 and 3, Ca (~6 mg/kg) or placebo (Pl) was ingested 1 hr beforehand in a double-blind manner and counterbalanced order. Subjects performed 3 sets to failure (BP and LP) with reps, PHR, and RPE recorded each set. Repeated-measures ANOVAs, 2 (trial) × 3 (set), were used to analyze dependent measures with the Tukey honestly significant difference used when necessary as the post hoc test.
In BP, no significant differences (Ca vs Pl) were observed (reps, RPE, PHR). During set 3 of LP training, Ca was associated with significantly higher reps (12.5 ± 4.2 vs 9.9 ± 2.6) and PHR (158.5 ± 11.9 vs 151.8 ± 13.2). No signifcant RPE differences were found during LP.
The findings of similar RPE concurrent with higher reps suggest that caffeine can blunt pain responses, possibly delaying fatigue in high-intensity resistance training. Ergogenic effects might be limited to the later sets in a resistance-training session. Further research is warranted regarding ergogenic effects of caffeine during resistance training and potential mechanisms of action.
Motor-Evoked Potentials for Early Individual Elements of an Action Sequence During Planning Reflect Parallel Activation Processes
Lawrence P. Behmer Jr., Mathew J.C. Crump, and Kelly J. Jantzen
Several computational models make predictions about the activation states of individual elements of an action sequence during planning and execution; however, the neural mechanisms of action planning are still poorly understood. Simple chaining models predict that only the first response in an action sequence should be active during planning. Conversely, some parallel activation models suggest that during planning, a serial inhibition process places the individual elements of the action into a serial order across a winner-takes-all competitive choice gradient in which earlier responses are more active, and hence likely to be selected for execution compared with later responses. We triggered transcranial magnetic stimulation pulses at 200 or 400 ms after the onset of a five-letter word, in which all but one response was planned and typed with the left hand, except for a single letter which required a right index finger response exclusively at one of five serial positions. We measured the resulting motor-evoked potentials at the right index finger as a marker for the activation state of that planned response. We observed no difference in motor-evoked potential amplitude across any serial position when a right index finger response was planned at 200 ms after the onset of the word; however, we observed a graded pattern of activation at 400 ms, with earlier positions that required a right index finger response showing greater motor-evoked potentials amplitude compared with later positions. These findings provide empirical support for competitive queuing computational models of action planning.
Dietary Supplements for Improving Body Composition and Reducing Body Weight: Where Is the Evidence?
Melinda M. Manore
Weight-loss supplements typically fall into 1 of 4 categories depending on their hypothesized mechanism of action: products that block the absorption of fat or carbohydrate, stimulants that increase thermogenesis, products that change metabolism and improve body composition, and products that suppress appetite or give a sense of fullness. Each category is reviewed, and an overview of the current science related to their effectiveness is presented. While some weight-loss supplements produce modest effects (<2 kg weight loss), many have either no or few randomized clinical trials examining their effectiveness. A number of factors confound research results associated with the efficacy of weight-loss supplements, such as small sample sizes, short intervention periods, little or no follow-up, and whether the supplement is given in combination with an energy-restricted diet or increased exercise expenditure. There is no strong research evidence indicating that a specific supplement will produce significant weight loss (>2 kg), especially in the long term. Some foods or supplements such as green tea, fiber, and calcium supplements or dairy products may complement a healthy lifestyle to produce small weight losses or prevent weight gain over time. Weight-loss supplements containing metabolic stimulants (e.g., caffeine, ephedra, synephrine) are most likely to produce adverse side effects and should be avoided.
Inspiratory Muscle Training and Endurance: A Central Metabolic Control Perspective
Andrew M. Edwards and Raewyn E. Walker
The efficacy of inspiratory muscle training (IMT) has been the subject of considerable controversy in terms of whether it is beneficial to endurance athletes and because a convincing physiological rationale has not been identified to explain its mechanism of action. Early studies suggested that IMT was an ineffectual intervention for gains in either maximal aerobic power or endurance-specific performance. More rigorous recent research supports the observation that maximal aerobic power is not receptive to IMT; however, closer evaluation of both early and contemporary research indicates that responses to endurance-specific performance tests are sensitive to IMT. As the aim of endurance training is to improve endurance performance rather than maximal aerobic power, it is plausible that IMT may be useful in specific performance-related circumstances. Performance adaptations following IMT appear to be connected with post training reports of attenuated effort sensations, but this common observation has tended to be overlooked by researchers in preference for a reductionist explanation. This commentary examines the pertinent research and practical performance implications of IMT from the holistic perspective of complex central metabolic control.