The influence of ball in/out of play and possession in elite soccer: Towards a more valid measure of physical intensity during competitive match-play.

The physical demands of soccer match-play have typically been assessed using a low-resolution whole match approach ignoring whether the ball is in or out of play (BIP/BOP) and during these periods which team has possession. This study investigated the effect of fundamental match structure variables (BIP/BOP, in/out of possession) on the physical demands, and especially intensity, of elite match-play. For 1083 matches from a major European league, whole match duration, and player physical tracking data, were divided into BIP/BOP, and in/out of possession periods throughout the match, using on-ball event data. These distinct phases were used to derive absolute (m) and rate (m·min-1) of distance covered in total and within six speed categories during BIP/BOP and in/out possession. The rate of distance covered, an index of physical intensity, was >2-fold greater during BIP vs BOP. Whole match total distance covered was confounded by BIP time and poorly associated with physical intensity during BIP (r = 0.36). Whole match rates of distance covered substantially underestimated those during BIP, particularly for higher running speeds (∼-62%). Ball possession markedly effected physical intensity, with the rates of distance covered running (+31%), at high-speed (+30%) and in total (+7%) greater out than in possession. Whole match physical metrics underestimated the physical intensity during BIP, and thus the rate(s) of distance covered during BIP are recommended for accurate measurement of physical intensity in elite soccer. The greater demands of being out of possession support a possession-based tactical approach to minimise fatigue and its negative consequences.

This large-scale study utilising >1000 elite level competitive matches found profound differences in rate of distance covered between periods of BIP vs BOP, being 2-fold higher overall and 8- to 33-fold higher for the rates of distance covered within running, high-speed and sprinting speed categories.Consequently, commonly used whole match physical metrics, that incorporate both BIP and BOP, such as distances covered but even rates of distance covered, were not valid indices of physical intensity (rate of distance covered) during BIP.Thus a more valid and direct approach to quantifying physical intensity during elite soccer match-play as the rate of distance covered during BIP is proposed.Utilising a unique within-match analysis the effect of possession (i.e. in vs out) revealed that teams covered ≥30% more running and high-speed distance while out than in possession during BIP.

The User Experience of an Immersive and Interactive Wall Exergame in Older Adults.

Exergames are promising options for modulating the effects of aging on physical and cognitive functions. A new-generation immersive and interactive wall exergame (I2WE) has emerged in recent years, offering users freedom of movement as well as greater and varied interactions with other players, the environment, and the system than traditional games (e.g., Wii™, Kinect). These features could improve the user experience (UX) and thus the engagement and benefits of the intervention for older people. The purpose of this study was to determine whether this kind of exergame could be an effective tool for multidomain training for the elderly. An exploratory study was conducted with 38 healthy older adults who tested a single exergame session to evaluate the UX and the perceived enjoyment, as well as the session's workload and intensity. The results show that I2WE generates moderate-to-high physical intensity, following recommendations for older people, while the perceived exertion is lower. Moreover, it creates a positive UX that correlates with high perceived enjoyment while producing a suitable session's workload. I2WE appears to be an effective tool to promote physical activity while concurrently stimulating cognition in older adults. The intrinsic characteristics (i.e., immersion, combined physical and cognitive activity, interactions, complex motor skills, playfulness, and variety of collective games) give this new type of exergame a promising future. Future studies should be conducted to investigate the effects of an I2WE program on the physical and cognitive functions of older adults.

Integrated Physiological, Biomechanical, and Subjective Responses for the Selection of Assistive Level in Pedelec Cycling.

In recent decade, pedelec has become one of the most popular transportation modes due to its effectiveness in reducing physical effort. The effects of using pedelec as an alternative mode of exercise were explored in previous studies. However, the effects of pedelec parameters were not quantified for the self-selected gear ratio, random riding speed, and varied road slopes, which restricted its application. Hence, this study aimed to evaluate the effects of gear ratio and assistive torque and to determine the optimum riding condition regarding physiological, biomechanical, and subjective responses of the rider. The riding tests consisted of simulated slope (1.0 vs. 2.5% grade), gear ratio (light vs. heavy), and assistive levels (0.5, 1, 1.5, and 2), and the tests were conducted in a randomized order. A total of 19 non-athletes completed the riding tests to evaluate physiological [metabolic equivalent of task (MET), heart rate, and gross efficiency (GE)], biomechanical [muscle activity (expressed as reference voluntary contraction, RVC) and power output], and subjective responses [rating of perceived exertion (RPE) and sense of comfort (SC)]. The test conditions induced moderate to vigorous intensities (3.7-7.4 METs, 58.5-80.3% of maximal heart rate, 11.1-29.5% of RVC rectus femoris activity, and 9.4-14.2 RPEs). The effects of gear ratio and assistive level on the physiological responses were significant. Riding with the heavy gear ratio showed advantages in METs and GE. For the optimum assistive level selection, low GE and limited improvement in subjective responses suggested the impact of low-power output conditions. Overall, for the health pedelec commuters, riding with 0.75 W/kg power output with 50 rpm cadence is recommended to obtain the moderate intensity (4.7 METs) and the advantages in GE and subjective feelings. Moreover, the findings can be applied to exercise intensity control and save battery energy effectively in varying riding conditions.

The use of stimulus perception to account for variability in skin conductance responses to interoceptive stimuli.

Activity of the electrodermal response system is customarily expressed in relation to physical stimulus properties and not to perceived features. In situations where the delivery of physically identical stimuli can be challenging, such as in interoception research, this variability might pose a challenge for contemporary SCR analyses. Therefore, we investigated the extent to which activity in the electrodermal response system triggered by the delivery of interoceptive stimuli is better predicted by perceived intensity rather than physical input. For this purpose, we reanalyzed data from the baseline phase of a previous study (n = 60) in which skin conductance responses (SCRs) to innocuous esophageal stimulations of high and low intensities were recorded in addition to categorizations based on their perceived intensity (high or low). Using both peak scoring and model inversion methods, we found that the inclusion of stimulus perception as a predictor of the magnitude of the SCR increased model fit. These findings suggest that the inclusion of perception is a promising avenue to better model variability in psychophysiological responses to interoceptive stimuli.

Labor market engagement and the body mass index of working adults: Evidence from India.

Galvanized by rapid income growth, labor market transitions in the nature of jobs, and lifestyle factors, there has been an increase in rates of obesity in many developing countries. This paper examines the relationship between BMI and sector and physical intensity of work among urban adults in India. We document that BMI is positively and significantly associated with labor market inactivity. Women in white-collar work have about 1.01 kg/m2 higher BMI than women in blue-collar work. For working men, the comparable estimate is approximately 1.18 kg/m2. We find that the increase in overall BMI originates from those who are already at high levels of BMI. Further, relative to the non-working sample, employment in a blue-collar occupation is associated with a BMI penalty for men and women. We find suggestive evidence that the increase in BMI for women is driven by a decline in energy expenditure, while both a decrease in energy expenditure and an increase in energy intake are important in explaining BMI dynamics for men. These results are robust to a variety of specification and methodological checks, and suggest that the increasing trend in BMI may be attributed to the transition towards a more sedentary occupational structure. Overall our research underlines the important role played by occupational engagement in determining the general health of populations in developing countries.

Energy expenditure of physical activity in Korean adults and assessment of accelerometer accuracy by gender / 한국영양학회지

PURPOSE: The purpose of this study was to measure energy expenditure (EE) the metabolic equivalents (METs) of 13 common physical activities by using a portable telemetry gas exchange system (K4b2) and to assess the accuracy of the accelerometer (Actigraph GT3X+) by gender in Korean adults. METHODS: A total of 109 adults (54 males, 55 females) with normal BMI (body mass index) participated in this study. EE and METs of 13 selected activities were simultaneously measured by the K4b2 portable indirect calorimeter and predicted by the GT3X+ Actigraph accelerometer. The accuracy of the accelerometer was assessed by comparing the predicted with the measured EE and METs. RESULTS: EE (kcal/kg/hr) and METs of treadmill walking (3.2 km/h, 4.8 km/h and 5.6 km/h) and running (6.4 km/h) were significantly higher in female than in male participants (p < 0.05). On the other hand, the accelerometer significantly underestimated the EE and METs for all activities except descending stairs, moderate walking, and fast walking in males as well as descending stairs in females. Low intensity activities had the highest rate of accurate classifications (88.3% in males and 91.3% females), whereas vigorous intensity activities had the lowest rate of accurate classifications (43.6% in males and 27.7% in females). Across all activities, the rate of accurate classification was significantly higher in males than in females (75.2% and 58.3% respectively, p < 0.01). Error between the accelerometer and K4b2 was smaller in males than in females, and EE and METs were more accurately estimated during treadmill activities than other activities in both males and females. CONCLUSION: The accelerometer underestimated EE and METs across various activities in Korean adults. In addition, there appears to be a gender difference in the rate of accurate accelerometer classification of activities according to intensity. Our results indicate the need to develop new accelerometer equations for this population, and gender differences should be considered.