Effects of α-lactalbumin on strength, fatigue and psychological parameters: a randomised double-blind cross-over study
- Mackay-Phillips, Karen, Orssatto, Lucas, Polman, Remco, Van der Pols, Jolieke, Trajano, Gabriel
- Authors: Mackay-Phillips, Karen , Orssatto, Lucas , Polman, Remco , Van der Pols, Jolieke , Trajano, Gabriel
- Date: 2023
- Type: Text , Journal article
- Relation: European Journal of Applied Physiology Vol. 123, no. 2 (2023), p. 381-393
- Full Text:
- Reviewed:
- Description: Purpose: The neurotransmitter serotonin has a strong effect on behaviour and motor control. Regarding motor control, serotonin contributes to the development of fatigue and is also involved in the ability of motor neurones to operate across a large range of forces (gain control). The consumption of tryptophan-rich supplements (such as
- Description: Purpose: The neurotransmitter serotonin has a strong effect on behaviour and motor control. Regarding motor control, serotonin contributes to the development of fatigue and is also involved in the ability of motor neurones to operate across a large range of forces (gain control). The consumption of tryptophan-rich supplements (such as α-lactalbumin) is of interest because this amino acid is the only precursor for brain serotonin synthesis. Therefore, the purpose of this study was to determine the effects of α-lactalbumin supplementation on neuromuscular performance. Methods: Using a randomised double-blind cross-over design, 16 healthy participants performed plantar flexor and handgrip maximal voluntary contractions, a 30-s submaximal handgrip contraction, and a plantar flexor fatigue protocol before and 90 min after consuming either 40 g of α-lactalbumin, an isonitrogenous beverage (Zein) or an isocaloric beverage (corn-starch). Sleepiness, mood, and cognition were assessed to evaluate any psychological effects. Results: α-Lactalbumin decreased force steadiness by 25% during the sustained submaximal handgrip contraction (p < 0.01) and induced greater fatigue (15% reduction in total torque–time integral, p = 0.01) during the fatigue protocol. These effects were not observed for the other control beverages. No effects were found for maximal or explosive strength, or psychological measurements. Conclusions: 40 g of α-lactalbumin increased handgrip force variability and reduced performance during fatiguing muscle contractions but did not influence brief maximal contractions or psychological parameters in healthy individuals. These findings support the hypothesis that the consumption of α-lactalbumin can increase motor neurone input–output gain and exacerbate central fatigue during sustained maximal exercise. © 2022, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.
- Authors: Mackay-Phillips, Karen , Orssatto, Lucas , Polman, Remco , Van der Pols, Jolieke , Trajano, Gabriel
- Date: 2023
- Type: Text , Journal article
- Relation: European Journal of Applied Physiology Vol. 123, no. 2 (2023), p. 381-393
- Full Text:
- Reviewed:
- Description: Purpose: The neurotransmitter serotonin has a strong effect on behaviour and motor control. Regarding motor control, serotonin contributes to the development of fatigue and is also involved in the ability of motor neurones to operate across a large range of forces (gain control). The consumption of tryptophan-rich supplements (such as
- Description: Purpose: The neurotransmitter serotonin has a strong effect on behaviour and motor control. Regarding motor control, serotonin contributes to the development of fatigue and is also involved in the ability of motor neurones to operate across a large range of forces (gain control). The consumption of tryptophan-rich supplements (such as α-lactalbumin) is of interest because this amino acid is the only precursor for brain serotonin synthesis. Therefore, the purpose of this study was to determine the effects of α-lactalbumin supplementation on neuromuscular performance. Methods: Using a randomised double-blind cross-over design, 16 healthy participants performed plantar flexor and handgrip maximal voluntary contractions, a 30-s submaximal handgrip contraction, and a plantar flexor fatigue protocol before and 90 min after consuming either 40 g of α-lactalbumin, an isonitrogenous beverage (Zein) or an isocaloric beverage (corn-starch). Sleepiness, mood, and cognition were assessed to evaluate any psychological effects. Results: α-Lactalbumin decreased force steadiness by 25% during the sustained submaximal handgrip contraction (p < 0.01) and induced greater fatigue (15% reduction in total torque–time integral, p = 0.01) during the fatigue protocol. These effects were not observed for the other control beverages. No effects were found for maximal or explosive strength, or psychological measurements. Conclusions: 40 g of α-lactalbumin increased handgrip force variability and reduced performance during fatiguing muscle contractions but did not influence brief maximal contractions or psychological parameters in healthy individuals. These findings support the hypothesis that the consumption of α-lactalbumin can increase motor neurone input–output gain and exacerbate central fatigue during sustained maximal exercise. © 2022, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.
The effects of α-lactalbumin supplementation and handgrip contraction on soleus motoneuron excitability
- Mackay-Phillips, Karen, Orssatto, Lucas, Polman, Remco, Van der Pols, Jolieke, Trajano, Gabriel
- Authors: Mackay-Phillips, Karen , Orssatto, Lucas , Polman, Remco , Van der Pols, Jolieke , Trajano, Gabriel
- Date: 2023
- Type: Text , Journal article
- Relation: European Journal of Applied Physiology Vol. 123, no. 2 (2023), p. 395-404
- Full Text:
- Reviewed:
- Description: Introduction: We tested two strategies that hypothetically increase serotonin availability (
- Description: Introduction: We tested two strategies that hypothetically increase serotonin availability (α-lactalbumin consumption and a remote submaximal handgrip contraction) on estimates of persistent inward currents (PICs) amplitude of soleus muscle in healthy participants. Methods: With a randomised, double-blind, and cross-over design, 13 healthy participants performed triangular-shaped ramp contractions with their plantar flexors (20% of maximal torque), followed by a 30-s handgrip sustained contraction (40% of maximal force) and consecutive repeated triangular-shaped contractions. This was performed before and after the consumption of either 40 g of α-lactalbumin, an isonitrogenous beverage (Zein) or an isocaloric beverage (Corn-starch). Soleus motor units discharge rates were analysed from high-density surface electromyography signals. PICs were estimated by calculating the delta frequency (ΔF) of motor unit train spikes using the paired motor unit technique. Results: ΔF (0.19 pps; p = 0.001; d = 0.30) and peak discharge rate (0.20 pps; p < 0.001; d = 0.37) increased after the handgrip contraction, irrespective of the consumed supplement. No effects of α-lactalbumin were observed. Conclusions: Our results indicate that 40 g of α-lactalbumin was unable to modify intrinsic motoneuron excitability. However, performing a submaximal handgrip contraction before the plantar flexion triangular contraction was capable of increasing ΔF and discharge rates on soleus motor units. These findings highlight the diffused effects of serotonergic input, its effects on motoneuron discharge behaviour, and suggest a cross-effector effect within human motoneurons. © 2022, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature. Erratum: Correction to: The effects of α‑lactalbumin supplementation and handgrip contraction on soleus motoneuron excitability - The original version of this article unfortunately contained a mistake. The corrected details are given below for your reading. The author’s name Karen Mackay-Phillips was incorrectly written as Karen Mackay Phillips. In section “Overview”, first sentence should read as “The current study was part of an experiment that has been divided in two parts, where some variables are presented in a companion paper (https:// doi. org/ 10. 1007/ s00421- 022- 05103-1).”. © 2022 Springer-Verlag GmbH Germany, part of Springer Nature.
- Authors: Mackay-Phillips, Karen , Orssatto, Lucas , Polman, Remco , Van der Pols, Jolieke , Trajano, Gabriel
- Date: 2023
- Type: Text , Journal article
- Relation: European Journal of Applied Physiology Vol. 123, no. 2 (2023), p. 395-404
- Full Text:
- Reviewed:
- Description: Introduction: We tested two strategies that hypothetically increase serotonin availability (
- Description: Introduction: We tested two strategies that hypothetically increase serotonin availability (α-lactalbumin consumption and a remote submaximal handgrip contraction) on estimates of persistent inward currents (PICs) amplitude of soleus muscle in healthy participants. Methods: With a randomised, double-blind, and cross-over design, 13 healthy participants performed triangular-shaped ramp contractions with their plantar flexors (20% of maximal torque), followed by a 30-s handgrip sustained contraction (40% of maximal force) and consecutive repeated triangular-shaped contractions. This was performed before and after the consumption of either 40 g of α-lactalbumin, an isonitrogenous beverage (Zein) or an isocaloric beverage (Corn-starch). Soleus motor units discharge rates were analysed from high-density surface electromyography signals. PICs were estimated by calculating the delta frequency (ΔF) of motor unit train spikes using the paired motor unit technique. Results: ΔF (0.19 pps; p = 0.001; d = 0.30) and peak discharge rate (0.20 pps; p < 0.001; d = 0.37) increased after the handgrip contraction, irrespective of the consumed supplement. No effects of α-lactalbumin were observed. Conclusions: Our results indicate that 40 g of α-lactalbumin was unable to modify intrinsic motoneuron excitability. However, performing a submaximal handgrip contraction before the plantar flexion triangular contraction was capable of increasing ΔF and discharge rates on soleus motor units. These findings highlight the diffused effects of serotonergic input, its effects on motoneuron discharge behaviour, and suggest a cross-effector effect within human motoneurons. © 2022, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature. Erratum: Correction to: The effects of α‑lactalbumin supplementation and handgrip contraction on soleus motoneuron excitability - The original version of this article unfortunately contained a mistake. The corrected details are given below for your reading. The author’s name Karen Mackay-Phillips was incorrectly written as Karen Mackay Phillips. In section “Overview”, first sentence should read as “The current study was part of an experiment that has been divided in two parts, where some variables are presented in a companion paper (https:// doi. org/ 10. 1007/ s00421- 022- 05103-1).”. © 2022 Springer-Verlag GmbH Germany, part of Springer Nature.
XR programmers give their perspective on how XR technology can be effectively utilised in high-performance sport
- Le Noury, Peter, Polman, Remco, Maloney, Michael, Gorman, Adam
- Authors: Le Noury, Peter , Polman, Remco , Maloney, Michael , Gorman, Adam
- Date: 2023
- Type: Text , Journal article
- Relation: Sports Medicine - Open Vol. 9, no. 1 (2023), p.
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- Description: Background: The successful use of extended reality (XR) in sport is highly dependent on the extent to which it can represent the perception–action couplings that exist in the performance setting. However, there are many unknowns regarding the effectiveness of XR technology which is limiting its adoption in sport. Therefore, providing high-performance sporting organisations with more information about the efficacy and utility of XR, specifically its strengths and limitations, is warranted. Results: The results provide insight into the limitations of XR and how those limitations are likely to reduce the effectiveness of XR for training motor skills. The participants described opportunities provided by XR for measuring athlete performance and highlighted several practical applications for enhancing athlete and coaching performance. Using artificial intelligence (AI) for training tactical decision-making and creating new movement solutions was also a key finding. Conclusions: The use of XR in sport is in its infancy, and more research is required to establish a deeper understanding of its utility and efficacy. This research provides sporting organisations, coaches, athletes, and XR technology companies with insights into where XR technology can have the greatest positive impact on performance in sport. © 2023, The Author(s).
- Authors: Le Noury, Peter , Polman, Remco , Maloney, Michael , Gorman, Adam
- Date: 2023
- Type: Text , Journal article
- Relation: Sports Medicine - Open Vol. 9, no. 1 (2023), p.
- Full Text:
- Reviewed:
- Description: Background: The successful use of extended reality (XR) in sport is highly dependent on the extent to which it can represent the perception–action couplings that exist in the performance setting. However, there are many unknowns regarding the effectiveness of XR technology which is limiting its adoption in sport. Therefore, providing high-performance sporting organisations with more information about the efficacy and utility of XR, specifically its strengths and limitations, is warranted. Results: The results provide insight into the limitations of XR and how those limitations are likely to reduce the effectiveness of XR for training motor skills. The participants described opportunities provided by XR for measuring athlete performance and highlighted several practical applications for enhancing athlete and coaching performance. Using artificial intelligence (AI) for training tactical decision-making and creating new movement solutions was also a key finding. Conclusions: The use of XR in sport is in its infancy, and more research is required to establish a deeper understanding of its utility and efficacy. This research provides sporting organisations, coaches, athletes, and XR technology companies with insights into where XR technology can have the greatest positive impact on performance in sport. © 2023, The Author(s).
A qualitative analysis of the perceived determinants of success in elite esports athletes
- Poulus, Dylan, Coulter, Tristan, Trotter, Michael, Polman, Remco
- Authors: Poulus, Dylan , Coulter, Tristan , Trotter, Michael , Polman, Remco
- Date: 2022
- Type: Text , Journal article
- Relation: Journal of Sports Sciences Vol. 40, no. 7 (2022), p. 742-753
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- Description: The current study aimed to qualitatively investigate the perceived determinants of success in professional esports athletes. Guided by the bioecological model (Bronfenbrenner & Morris, 2006), thematic analysis was used to explore elite esports athletes’ perceptions of success determinants. Semi-structured interviews were conducted with seven elite esports athletes. The interviews were used to investigate players’ psychology when playing well, training in elite esports, and working in esports teams. Deductive and inductive analyses were conducted to capture the core themes of success in esports within the bioecological model. When playing well, elite esports athletes experienced high levels of confidence, uninterrupted focus, and flow states. Elite esport athletes use mental strategies to help regulate their emotions and remain mindful in the presence of “tilt”. Furthermore, breathing techniques and tactical breaks were used when players felt nervous or when trying to “reset” from a stressful situation. When working in elite esport teams, players reported using strategies to improve team cohesion and that the biggest challenge was interpersonal disagreements. The results contribute to the growing body of literature highlighting the psychological similarities between elite esports and traditional sports athletes and serve as an index for future research into high-performance in esports. © 2021 Informa UK Limited, trading as Taylor & Francis Group.
- Authors: Poulus, Dylan , Coulter, Tristan , Trotter, Michael , Polman, Remco
- Date: 2022
- Type: Text , Journal article
- Relation: Journal of Sports Sciences Vol. 40, no. 7 (2022), p. 742-753
- Full Text:
- Reviewed:
- Description: The current study aimed to qualitatively investigate the perceived determinants of success in professional esports athletes. Guided by the bioecological model (Bronfenbrenner & Morris, 2006), thematic analysis was used to explore elite esports athletes’ perceptions of success determinants. Semi-structured interviews were conducted with seven elite esports athletes. The interviews were used to investigate players’ psychology when playing well, training in elite esports, and working in esports teams. Deductive and inductive analyses were conducted to capture the core themes of success in esports within the bioecological model. When playing well, elite esports athletes experienced high levels of confidence, uninterrupted focus, and flow states. Elite esport athletes use mental strategies to help regulate their emotions and remain mindful in the presence of “tilt”. Furthermore, breathing techniques and tactical breaks were used when players felt nervous or when trying to “reset” from a stressful situation. When working in elite esport teams, players reported using strategies to improve team cohesion and that the biggest challenge was interpersonal disagreements. The results contribute to the growing body of literature highlighting the psychological similarities between elite esports and traditional sports athletes and serve as an index for future research into high-performance in esports. © 2021 Informa UK Limited, trading as Taylor & Francis Group.
Home advantage and LBW decisions : the contribution of umpiring to the home-ground (dis)advantage in cricket
- Adie, Joshua, Renshaw, Ian, Polman, Remco, Mann, David
- Authors: Adie, Joshua , Renshaw, Ian , Polman, Remco , Mann, David
- Date: 2022
- Type: Text , Journal article
- Relation: Journal of Science and Medicine in Sport Vol. 25, no. 6 (2022), p. 520-523
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- Description: Objectives: This study aimed to determine whether elite cricket umpires' decisions contribute to home advantage via leg-before-wicket decisions. Design: Leg-before-wicket decisions (n = 4971) from actual elite level cricket matches in Australia between 2009 and 2016 were analysed using a binomial logistic regression to predict the umpires' leg-before-wicket decisions. Methods: Regressions were performed to determine whether the batter's team (home or away) influenced the likelihood that the umpire would give them out leg-before-wicket. Results: We found no evidence of home advantage in umpires' leg-before-wicket decisions. In fact, we found evidence that umpires in some instances disadvantage the home team. Conclusions: We suggest that the increased professionalism of sports officials, and the scrutiny they are placed under, may lead umpires to reduce or even overcompensate for any existing biases in their decision making. © 2022 Sports Medicine Australia
- Authors: Adie, Joshua , Renshaw, Ian , Polman, Remco , Mann, David
- Date: 2022
- Type: Text , Journal article
- Relation: Journal of Science and Medicine in Sport Vol. 25, no. 6 (2022), p. 520-523
- Full Text:
- Reviewed:
- Description: Objectives: This study aimed to determine whether elite cricket umpires' decisions contribute to home advantage via leg-before-wicket decisions. Design: Leg-before-wicket decisions (n = 4971) from actual elite level cricket matches in Australia between 2009 and 2016 were analysed using a binomial logistic regression to predict the umpires' leg-before-wicket decisions. Methods: Regressions were performed to determine whether the batter's team (home or away) influenced the likelihood that the umpire would give them out leg-before-wicket. Results: We found no evidence of home advantage in umpires' leg-before-wicket decisions. In fact, we found evidence that umpires in some instances disadvantage the home team. Conclusions: We suggest that the increased professionalism of sports officials, and the scrutiny they are placed under, may lead umpires to reduce or even overcompensate for any existing biases in their decision making. © 2022 Sports Medicine Australia
Reliability of the ICECAP-O quality of life scale with community-dwelling people with dementia
- Bibi, Iram, Polman, Remco, Nyman, Samuel
- Authors: Bibi, Iram , Polman, Remco , Nyman, Samuel
- Date: 2022
- Type: Text , Journal article
- Relation: Gerontology and Geriatric Medicine Vol. 8, no. (2022), p.
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- Description: Currently, measures of quality of life used with older people with dementia (PWD) are mainly health related. Health is not an actual attribute of but a means to attain quality of life. The Investigating Choice Experiments for the Preferences of Older People - CAPability index (ICECAP-O) measures attributes of quality of life. While its construct validity has been tested with PWD, no study has yet published data on the reliability of this scale used directly with PWD. In this study, we tested the external (test-retest) reliability of the ICECAP-O with 54 community-dwelling older PWD from the south of England. The ICECAP-O had acceptable test-retest reliability (r =.68, p <.01 and r =.56, p <.01 for raw and tariff scores, respectively). This suggests that the ICECAP-O is both a reliable and valid measure of quality of life for use directly with community-dwelling PWD. © The Author(s) 2022.
- Authors: Bibi, Iram , Polman, Remco , Nyman, Samuel
- Date: 2022
- Type: Text , Journal article
- Relation: Gerontology and Geriatric Medicine Vol. 8, no. (2022), p.
- Full Text:
- Reviewed:
- Description: Currently, measures of quality of life used with older people with dementia (PWD) are mainly health related. Health is not an actual attribute of but a means to attain quality of life. The Investigating Choice Experiments for the Preferences of Older People - CAPability index (ICECAP-O) measures attributes of quality of life. While its construct validity has been tested with PWD, no study has yet published data on the reliability of this scale used directly with PWD. In this study, we tested the external (test-retest) reliability of the ICECAP-O with 54 community-dwelling older PWD from the south of England. The ICECAP-O had acceptable test-retest reliability (r =.68, p <.01 and r =.56, p <.01 for raw and tariff scores, respectively). This suggests that the ICECAP-O is both a reliable and valid measure of quality of life for use directly with community-dwelling PWD. © The Author(s) 2022.
Short-term effect of additional daily dietary fibre intake on appetite, satiety, gastrointestinal comfort, acceptability, and feasibility
- Borkoles, Erika, Krastins, Digby, van der Pols, Jolieke, Sims, Paul, Polman, Remco
- Authors: Borkoles, Erika , Krastins, Digby , van der Pols, Jolieke , Sims, Paul , Polman, Remco
- Date: 2022
- Type: Text , Journal article
- Relation: Nutrients Vol. 14, no. 19 (2022), p.
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- Description: Background: There is evidence that high-fibre diets have significant health benefits, although the effect of increasing fibre on individuals’ appetite, satiety, and gastrointestinal comfort is not well established, nor is its acceptability and feasibility. Methods: This mixed-methods feasibility randomised control trial included 38 participants allocated to one of three conditions: FibreMAX (two daily servings of 25 g of BARLEYmax®), FibreGRAD (two daily servings with the amount of fibre gradually increased), and Control (two daily servings totalling 25 g of placebo product). Participants completed a food diary at baseline. The Hunger and Fullness Questionnaire and questions regarding gastrointestinal response were completed at baseline and at the end of each week. Participants completed the acceptability of intervention measure and engaged in a semi-structured interview, following trial completion. Results: The qualitative data suggested that increased fibre influenced appetite and fullness perceptions. Baseline fibre consumption and the method of increased fibre increase did not influence our findings. The qualitative results also indicated that the fibre intake was perceived as beneficial to well-being; it influenced feelings of hunger and caused some minor acute gastrointestinal symptoms that dissipated after a short adaption period. Conclusion: This study suggests that increasing fibre intake through BARLEYmax® is a safe intervention that is acceptable to participants. © 2022 by the authors.
- Authors: Borkoles, Erika , Krastins, Digby , van der Pols, Jolieke , Sims, Paul , Polman, Remco
- Date: 2022
- Type: Text , Journal article
- Relation: Nutrients Vol. 14, no. 19 (2022), p.
- Full Text:
- Reviewed:
- Description: Background: There is evidence that high-fibre diets have significant health benefits, although the effect of increasing fibre on individuals’ appetite, satiety, and gastrointestinal comfort is not well established, nor is its acceptability and feasibility. Methods: This mixed-methods feasibility randomised control trial included 38 participants allocated to one of three conditions: FibreMAX (two daily servings of 25 g of BARLEYmax®), FibreGRAD (two daily servings with the amount of fibre gradually increased), and Control (two daily servings totalling 25 g of placebo product). Participants completed a food diary at baseline. The Hunger and Fullness Questionnaire and questions regarding gastrointestinal response were completed at baseline and at the end of each week. Participants completed the acceptability of intervention measure and engaged in a semi-structured interview, following trial completion. Results: The qualitative data suggested that increased fibre influenced appetite and fullness perceptions. Baseline fibre consumption and the method of increased fibre increase did not influence our findings. The qualitative results also indicated that the fibre intake was perceived as beneficial to well-being; it influenced feelings of hunger and caused some minor acute gastrointestinal symptoms that dissipated after a short adaption period. Conclusion: This study suggests that increasing fibre intake through BARLEYmax® is a safe intervention that is acceptable to participants. © 2022 by the authors.
The effect of an 8 week prescribed exercise and low-carbohydrate diet on cardiorespiratory fitness, body composition and cardiometabolic risk factors in obese individuals: A randomised controlled trial
- Perissiou, Maria, Borkoles, Erika, Kobayashi, Kent, Polman, Remco
- Authors: Perissiou, Maria , Borkoles, Erika , Kobayashi, Kent , Polman, Remco
- Date: 2020
- Type: Text , Journal article
- Relation: Nutrients Vol. 12, no. 2 (2020), p. 482
- Full Text:
- Reviewed:
- Description: Low-carbohydrate (LC) diets are an effective method for treating obesity and reducing cardiometabolic risk. However, exposure to LC diets is associated with reductions in muscle mass and increased osteoporosis risk in obese individuals. The combination of exercise with a LC diet appears to attenuate muscle mass loss induced by LC diets alone, and to further improve cardiometabolic profile. However, evidence to date in obese individuals is limited. We assessed the effect of LC diet in combination with supervised exercise on cardiorespiratory fitness, body composition and cardiometabolic risk factors in obese individuals. Male and female participants in the experimental (EX-LC structured supervised exercise program + low-carbohydrate meals n = 33 35.3 years) and control (EX-CO structured supervised exercise program + standard dietary advice n = 31 34.2 years) conditions underwent measurements of cardiorespiratory fitness ( O peak), body fat, lean muscle mass (LMM), and cardiometabolic biomarkers before and after an 8 week intervention. : Participants in the EX-LC condition demonstrated greater improvements in O peak ( = 0.002) and fat mass index (FMI, = 0.001) compared to the EX-CO condition. Achieving a ketogenic state (β-hydroxybutyrate, βHB ≥0.3 mmol/L) was associated with greater reductions in total body fat ( = 0.011), visceral adipose tissue ( = 0.025), FMI ( = 0.002) and C-reactive protein (CRP, = 0.041) but also with greater reductions in LMM ( = 0.042). : Short-term LC diet combined with prescribed exercise enhanced cardiorespiratory fitness and the cardiometabolic profile of obese individuals but was also associated with greater muscle mass loss compared to similar exercise training and standard dietary advice. The long-term effects of the LC diet should be further explored in future studies.
- Authors: Perissiou, Maria , Borkoles, Erika , Kobayashi, Kent , Polman, Remco
- Date: 2020
- Type: Text , Journal article
- Relation: Nutrients Vol. 12, no. 2 (2020), p. 482
- Full Text:
- Reviewed:
- Description: Low-carbohydrate (LC) diets are an effective method for treating obesity and reducing cardiometabolic risk. However, exposure to LC diets is associated with reductions in muscle mass and increased osteoporosis risk in obese individuals. The combination of exercise with a LC diet appears to attenuate muscle mass loss induced by LC diets alone, and to further improve cardiometabolic profile. However, evidence to date in obese individuals is limited. We assessed the effect of LC diet in combination with supervised exercise on cardiorespiratory fitness, body composition and cardiometabolic risk factors in obese individuals. Male and female participants in the experimental (EX-LC structured supervised exercise program + low-carbohydrate meals n = 33 35.3 years) and control (EX-CO structured supervised exercise program + standard dietary advice n = 31 34.2 years) conditions underwent measurements of cardiorespiratory fitness ( O peak), body fat, lean muscle mass (LMM), and cardiometabolic biomarkers before and after an 8 week intervention. : Participants in the EX-LC condition demonstrated greater improvements in O peak ( = 0.002) and fat mass index (FMI, = 0.001) compared to the EX-CO condition. Achieving a ketogenic state (β-hydroxybutyrate, βHB ≥0.3 mmol/L) was associated with greater reductions in total body fat ( = 0.011), visceral adipose tissue ( = 0.025), FMI ( = 0.002) and C-reactive protein (CRP, = 0.041) but also with greater reductions in LMM ( = 0.042). : Short-term LC diet combined with prescribed exercise enhanced cardiorespiratory fitness and the cardiometabolic profile of obese individuals but was also associated with greater muscle mass loss compared to similar exercise training and standard dietary advice. The long-term effects of the LC diet should be further explored in future studies.
Social identification, exercise participation, and positive exercise experiences : evidence from parkrun
- Stevens, Mark, Rees, Tim, Polman, Remco
- Authors: Stevens, Mark , Rees, Tim , Polman, Remco
- Date: 2019
- Type: Text , Journal article
- Relation: Journal of Sports Sciences Vol. 37, no. 2 (2019), p. 221-228
- Full Text:
- Reviewed:
- Description: Growing evidence suggests that social identities may have profound implications for physical activity participation. Real-world examinations of this relationship have, however, been lacking, with research predominantly examining intentions and hypothetical scenarios. To address this shortcoming and further advance understanding in this area, the present study tested relationships between group identification, participation, two exercise-specific outcomes (exercise-specific satisfaction and group cohesion), and a broad health indicator (life satisfaction) among individuals recruited from parkrun. Participants (N = 289) completed questionnaires measuring all variables except participants’ parkrun participation, which was objectively assessed. Structural equation modeling demonstrated that group identification was significantly associated with greater participation, exercise-specific satisfaction, group cohesion, and life satisfaction. Findings provide real-world evidence of the health-related benefits associated with forming strong social identities in exercise settings. © 2018, © 2018 Informa UK Limited, trading as Taylor & Francis Group.
- Authors: Stevens, Mark , Rees, Tim , Polman, Remco
- Date: 2019
- Type: Text , Journal article
- Relation: Journal of Sports Sciences Vol. 37, no. 2 (2019), p. 221-228
- Full Text:
- Reviewed:
- Description: Growing evidence suggests that social identities may have profound implications for physical activity participation. Real-world examinations of this relationship have, however, been lacking, with research predominantly examining intentions and hypothetical scenarios. To address this shortcoming and further advance understanding in this area, the present study tested relationships between group identification, participation, two exercise-specific outcomes (exercise-specific satisfaction and group cohesion), and a broad health indicator (life satisfaction) among individuals recruited from parkrun. Participants (N = 289) completed questionnaires measuring all variables except participants’ parkrun participation, which was objectively assessed. Structural equation modeling demonstrated that group identification was significantly associated with greater participation, exercise-specific satisfaction, group cohesion, and life satisfaction. Findings provide real-world evidence of the health-related benefits associated with forming strong social identities in exercise settings. © 2018, © 2018 Informa UK Limited, trading as Taylor & Francis Group.
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