A role for exercise in attenuating unhealthy food consumption in response to stress

It is well established that both acute and chronic stress can be detrimental to health and wellbeing by directly increasing the risk of several chronic diseases and related health problems. In addition, stress may contribute to ill-health indirectly via its downstream effects on individuals' health-related behaviour, such as promoting the intake of unhealthy palatable foods high in fat and sugar content. This paper reviews (a) the research literature on stress-models; (b) recent research investigating stress-induced eating and (c) the potential physiological and psychological pathways contributing to stress-induced eating. Particular attention is given to (d) the role of physical exercise in attenuating acute stress, with exploration of potential mechanisms through which exercise may reduce unhealthy food and drink consumption subsequent to stressor exposure. Finally, exercise motivation is discussed as an important psychological influence over the capacity for physical exercise to attenuate unhealthy food and drink consumption after exposure to stressors. This paper aims to provide a better understanding of how physical exercise might alleviate stress-induced unhealthy food choices

THE CONTRIBUTION OF ELBOW EXTENSION TO WRIST SPEED IN CRICKET FAST BOWLERS

The purpose of this modelling study was to assess the sensitivity of wrist joint speed to systematic manipulations of empirical elbow joint flexion-extension kinematic profiles. The joint kinematic profiles of 12 cricket fast bowlers were entered into a Forward Kinematic Model and the elbow joint kinematic profiles were subsequently amplified to elicit wrist speed changes. An amplification factor of zero decreased wrist speed by a mean of 8.6% (± 6.9%), whereas an amplification factor of two increased speed by a mean of 8.8% (± 7.1%). An opposite relationship was found for two participants who extended the elbow joint prior to release and it is proposed that an internally rotated humerus will displace the wrist joint posteriorly when the elbow joint is extending

THE SYMMETRY ANGLE IDENTIFIES LESS CLINICALLY RELEVANT INTER-LIMB ASYMMETRIES THAN THE SYMMETRY INDEX IN HEALTHY ADULTS

There are several methods for calculating inter-limb symmetry, an inter-limb difference ≥15% has been suggested as an indicator of sporting injury risk. The purpose of this study was to compare three common methods for determining symmetry: the Symmetry Index (percentage difference; SI) when referenced to the left limb (SILeft) or the average of both limbs (SIAverage), and the Symmetry Angle (vector difference; SA). 15 recreationally active participants completed a sprint protocol on a non-motorised treadmill. Accelerometers were positioned on both tibias to measure peak resultant acceleration (PRA). The SA identified less clinically relevant PRA inter-limb asymmetries than the SI in healthy adults. Once an appropriate level of asymmetry as measured by the SA is determined, this may help to more correctly identify asymmetry in athletes and patients than the SI

Do dance floor force reduction and static stiffness represent dynamic floor stiffness during dance landings?

Dance training on floors that are not \u27sprung\u27 are assumed to have direct implications for injury. Standards for dance floor manufacture in Europe and North America quantify floor force reduction by measuring the impact forces of drop masses. In addition, many studies of human mechanical adaptations to varied surfaces, have quantified test surfaces using measures of static stiffness. It is unclear whether these methods for the measurement of floor mechanical properties actually reflect dancer requirements or floor behaviour under dancer loading. The aim of this study was to compare the force reduction, static stiffness and dynamic stiffness of a range of dance floors. Dynamic stiffness was measured during dancers performing drop landings. Force reduction highly correlated (p= 0.086) with floors of moderate dynamic stiffness, but was less accurate for high and low stiffness floors. Static stiffness underestimated the dynamic stiffness of the floors. Measurement of floor force reduction using European sports surface standards may provide an accurate representation of dynamic floor stiffness when under load from dancers performing drop landings. The discrepancy between static and dynamic stiffness may be explained by the inertial characteristics of the floor and the rapid loading of the floors during dancer landings. The development of portable systems for measuring floor behaviour under human loads using modern motion capture technologies may be beneficial for improving the quantification of dance floor mechanical properties

VALIDATION OF A DXA-BASED METHOD FOR OBTAINING INERTIA TENSORS: 'WHEN PIGS FLY'

This paper examines the accuracy of body segment inertia tensors estimated by combining information from dual-energy X-ray absorptiometry and a three-dimensional modelling technique proposed by Zatsiorsky et al. (1 990) (DXAIVol method). The inertia tensor of a frozen pig cadaver was estimated using the novel DXAlVol method and traditional compound pendulum techniques. The pig cadaver was projected through the air and the experimental 'ground truth kinematics' were recorded. Simulated kinematics of the pig cadaver flight were generated using the inertia tensor derived from the DXAlVol and compound pendulum methods and compared to the ground truth kinematics. Simulations based on the novel D W o l method's inertia tensor traded the experimentally recorded flight of the frozen pig cadaver with superior accuracy

Measurement of lower-limb asymmetry in professional rugby league: a technical note describing the use of inertial measurement units

Background. Quantifying lower-limb load and asymmetry during team sport match play may be important for injury prevention and understanding performance. However, current analysis methods of lower-limb symmetry during match-play employ wearable microtechnology that may not be best suited to the task. A popular microtechnology is global positioning systems (GPS), which are torso worn. The torso location, and the summary workload measures calculated by GPS are not suited to the calculation of lower-limb load. Instead, research grade accelerometers placed directly on the lower-limb may provide better load information than GPS. This study proposes a new technique to quantify external mechanical load, and lower-limb asymmetry during on-field team sport play using inertial measurement units. Methods. Four professional rugby league players (Age: 23.4 ± 3.1 years; Height: 1.89 ± 0.05 m; Mass: 107.0 ± 12.9 kg) wore two accelerometers, one attached to each foot by the boot laces, during match simulations. Custom Matlab (R2017b, The Mathworks Inc, Natick, MA) code was used to calculate total time, area under the curve (AUC), and percentage of time (%Time) spent in seven acceleration categories (negative to very high, <0 g to >16 g), as well as minimum and maximum acceleration during match simulations. Lower-limb AUC and %Time asymmetry was calculated using the Symmetry Angle Equation, which does not require normalization to a reference leg. Results. The range of accelerations experienced across all participants on the left and right sides were 15.68–17.53 g, and 16.18–17.69 g, respectively. Clinically significant asymmetry in AUC and %Time was observed for all but one participant, and only in negative (<0 g) and very high accelerations (>16 g). Clinically significant AUC differences in very high accelerations ranged from 19.10%–26.71%. Clinically significant %Time differences in negative accelerations ranged from 12.65%–25.14%, and in very high accelerations from 18.59%–25.30%. All participants experienced the most AUC at very low accelerations (2–4 g), and the least AUC at very high accelerations (165.00–194.00 AU vs. 0.32–3.59 AU). The %Time results indicated that all participants spent the majority of match-play (73.82–92.06%) in extremely low (0–2 g) to low (4–6 g) acceleration intensities, and the least %Time in very high accelerations (0.01%–0.05%). Discussion. A wearable located on the footwear to measure lower-limb load and asymmetry is feasible to use during rugby league match-play. The location of the sensor on the boot is suited to minimize injury risk occurring from impact to the sensor. This technique is able to quantify external mechanical load and detect inter limb asymmetries during match-play at the source of impact and loading, and is therefore likely to be better than current torso based methods. The results of this study may assist in preparing athletes for match-play, and in preventing injury

Pole dancing for fitness: The physiological and metabolic demand of a 60-minute class

Nicholas, JC, McDonald, KA, Peeling, P, Jackson, B, Dimmock, JA, Alderson, JA, and Donnelly, CJ. Pole dancing for fitness: The physiological and metabolic demand of a 60-minute class. J Strength Cond Res 33(10): 2704–2710, 2019—Little is understood about the acute physiological or metabolic demand of pole dancing classes. As such, the aims of this study were to quantify the demands of a standardized recreational pole dancing class, classifying outcomes according to American College of Sports Medicine (ACSM) exercise-intensity guidelines, and to explore differences in physiological and metabolic measures between skill- and routine-based class components. Fourteen advanced-level amateur female pole dancers completed three 60-minute standardized pole dancing classes. In one class, participants were fitted with a portable metabolic analysis unit. Overall, classes were performed at a mean Vo2 of 16.0 ml·kg−1·min−1, total energy cost (EC) of 281.6 kcal (4.7 kcal·min−1), metabolic equivalent (METs) of 4.6, heart rate of 131 b·min−1, rate of perceived exertion (RPE) of 6.3/10, and blood lactate of 3.1 mM. When comparing skill- and routine-based components of the class, EC per minute (4.4 vs. 5.3 kcal·min−1), peak Vo2 (21.5 vs. 29.6 ml·kg−1·min−1), METs (4.3 vs. 5.2), and RPE (7.2 vs. 8.4) were all greater in the routine-based component (p \u3c 0.01), indicating that classes with an increased focus on routine-based training, as compared to skill-based training, may benefit those seeking to exercise at a higher intensity level, resulting in greater caloric expenditure. In accordance with ASCM guidelines, an advanced-level 60-minute pole dancing class can be classified as a moderate-intensity cardiorespiratory exercise; when completed for ≥ 30 minutes, ≥ 5 days per week (total ≥ 150 minutes) satisfies the recommended level of exercise for improved health and cardiorespiratory fitness

Pole dancing for fitness: The physiological and metabolic demand of a 60-minute class

Nicholas, JC, McDonald, KA, Peeling, P, Jackson, B, Dimmock, JA, Alderson, JA, and Donnelly, CJ. Pole dancing for fitness: The physiological and metabolic demand of a 60-minute class. J Strength Cond Res 33(10): 2704–2710, 2019—Little is understood about the acute physiological or metabolic demand of pole dancing classes. As such, the aims of this study were to quantify the demands of a standardized recreational pole dancing class, classifying outcomes according to American College of Sports Medicine (ACSM) exercise-intensity guidelines, and to explore differences in physiological and metabolic measures between skill- and routine-based class components. Fourteen advanced-level amateur female pole dancers completed three 60-minute standardized pole dancing classes. In one class, participants were fitted with a portable metabolic analysis unit. Overall, classes were performed at a mean Vo2 of 16.0 ml·kg−1·min−1, total energy cost (EC) of 281.6 kcal (4.7 kcal·min−1), metabolic equivalent (METs) of 4.6, heart rate of 131 b·min−1, rate of perceived exertion (RPE) of 6.3/10, and blood lactate of 3.1 mM. When comparing skill- and routine-based components of the class, EC per minute (4.4 vs. 5.3 kcal·min−1), peak Vo2 (21.5 vs. 29.6 ml·kg−1·min−1), METs (4.3 vs. 5.2), and RPE (7.2 vs. 8.4) were all greater in the routine-based component (p \u3c 0.01), indicating that classes with an increased focus on routine-based training, as compared to skill-based training, may benefit those seeking to exercise at a higher intensity level, resulting in greater caloric expenditure. In accordance with ASCM guidelines, an advanced-level 60-minute pole dancing class can be classified as a moderate-intensity cardiorespiratory exercise; when completed for ≥ 30 minutes, ≥ 5 days per week (total ≥ 150 minutes) satisfies the recommended level of exercise for improved health and cardiorespiratory fitness