Med Sci Sports Exerc Research Articles

Relationship between muscle venous blood oxygenation and near-infrared spectroscopy: quantitative analysis of the Hb and Mb contributions.

A linear relationship between skeletal muscle venous ([Formula: see text]) and oxygenated (ΔHbMbO2,N) or deoxygenated (ΔHHbMbN) near-infrared spectroscopy (NIRS) signals suggest a main hemoglobin (Hb) contribution to the NIRS signal. However, experimental, and computational evidence supports a significant contribution of myoglobin (Mb) to the NIRS. Venous and NIRS measurements from a canine model of muscle oxidative metabolism (Sun Y, Ferguson BS, Rogatzki MJ, McDonald JR, Gladden LB. Med Sci Sports Exerc 48(10):2013-2020, 2016) were integrated into a computational model of muscle O2 transport and utilization to evaluate whether the relationship between venous and NIRS oxygenation can be affected by a significant Mb contribution to the NIRS signals. The mathematical model predicted well the measure of the changes of [Formula: see text] and NIRS signals for different O2 delivery conditions (blood flow, arterial O2 content) in muscle at rest (T1, T2) and during contraction (T3). Furthermore, computational analysis indicates that for adequate O2 delivery, Mb contribution to NIRS signals was significant (20%-30%) even in the presence of a linear [Formula: see text]-NIRS relationship; for a reduced O2 delivery the nonlinearity of the [Formula: see text]-NIRS relationship was related to the Mb contribution (50%). In this case (T3), the deviation from linearity is observed when O2 delivery is reduced from 1.3 to 0.7 L kg-1·min-1 ([Formula: see text] < 10 mLO2 100 mL-1) and Mb saturation decreased from 85% to 40% corresponding to an increase of the Mb contribution to ΔHHbMbN from 15% to 50% and the contribution to ΔHbMbO2,N from 0% to 30%. In contrast to a common assumption, our model indicates that both NIRS signals (ΔHHbMbN and ΔHbMbO2,N are significantly affected by Hb and Mb oxygenation changes.NEW & NOTEWORTHY Within the near-infrared spectroscopy (NIRS) signal, the contribution from hemoglobin is indistinguishable from that of myoglobin. A computation analysis indicates that a linear relationship between muscle venous oxygen content and NIRS signals does not necessarily indicate a negligible myoglobin contribution to the NIRS signal. A reduced oxygen delivery increases the myoglobin contribution to the NIRS signal. The integrative approach proposed is a powerful way to assist in interpreting the elements from which the NIRS signals are derived.

Steep ramp test protocol for preoperative risk assessment and short-term high-intensity interval training to evaluate, improve, and monitor cardiorespiratory fitness in surgical oncology.

Steep ramp test protocol for preoperative risk assessment and short-term high-intensity interval training to evaluate, improve, and monitor cardiorespiratory fitness in surgical oncology.

Stimulant use by athletes

Stimulant use by athletes

Sex Differences In Marathon Performance Are Larger In The Past Decade Than Expected Physiologically

The sex difference in performance of marathon runners historically has been larger than explained by physiological differences, possibly reflecting lower participation of females (1). The number of female participants across all age groups has increased in recent decades, but it is unclear if the sex difference in performance has continued to diminish. PURPOSE: To determine the sex difference in performance in the New York City (NYC) marathon across age groups, and with the place of runner (1st-10th place), in the past decade and relative to earlier published data (1980-2010) (1). METHODS: Running times of the top 10 placed male and female finishers (5-year age groups) who competed in the NYC marathon (2009-2019) were retrieved from a public database (https://results.nyrr.org/races). Univariate ANOVA determined the sex difference in the mean running velocity; (% Δ males and females/males) across age groups and place. RESULTS: The sex difference in running velocity increased across age groups (p < 0.001). For 2015-2019, the 30-39-year olds had the smallest difference (12.9 ± 0.5%) and the 70-79 year olds the largest (22.9 ± 0.9%). Across all age groups, the sex difference in running velocity decreased across years from 22.0 ± 0.4% in 1980-84 to 16.1 ± 0.2% in 2005-2009 and plateaued for the subsequent decade. The largest drop was in the two older age groups (60-79 years, 36% to 21%) and the least for youngest (20-49 years, 18% to 12.5%). Across all age groups, the sex difference in running velocity for 1st placed runners was 15.9 ± 0.4 % and increased to 20.3 ± 0.3% for 10th (P < 0.001). The greatest increase in the sex difference (1st to 10th) was in the 70-79 age group (21.9 ± 1.5% to 31.6 ± 1.7%) and the least in the 40-49 age group (13.9 ± 0.6% to 17.8 ± 0.4%). CONCLUSION: The largest sex differences in marathon performance were within the older age groups and lower (slower)-placed runners. Across all age groups, the sex difference in performance plateaued in the past 15 years despite more female participants and the continued decrease in male:female participation ratios. These results also suggest that physiological and sociological factors that impact the sex difference in running velocity vary by age group. (1) Hunter SK, et al Med Sci Sports Exerc 45: 148-156, 2013.

Reproductive health and stress fracture risk: a wearables solution

Introduction: Insulin-like growth factor 1 (IGF-I) is a mitogenic and metabolic growth factor that can act both systemically and locally, being produced predominantly in the liver but also by other tissues including the brain, kidneys, muscle, and bone1,2. IGF-I is well-established as an important mediator of bone formation, remodelling, and repair and can be easily measured in serum. IGF-I stimulates osteoblast proliferation, bone matrix protein synthesis, alkaline phosphatase activity and differentiation. Loss of IGF-I results in decreased long bone size, reduced growth plates, and delayed formation of secondary ossification centers in mice. Conversely, transgenic mice with osteoblast-targeted overexpression of IGF-I demonstrate an accelerated bone formation rate with increased bone mineral density (BMD) and trabecular and cortical bone volume. The essential nature of IGF-I in bone development is recapitulated in humans. Individuals with disruptions in the IGF-I gene causing reduced serum IGF-I concentrations have a severe reduction in peak BMD compared to normal age-matched individuals. Methods: This presentation will provide an overview of the relationship between the IGF-I system and bone health and remodelling, with a particular emphasis toward military relevance and utility of measuring IGF-I during military training2,3. Because the IGF-I system is involved in bone formation, remodelling, and repair, female recruits sustaining stress fractures during military training would be of special interest with regard to differential circulating concentrations of IGF-I system components compared to their uninjured female counterparts. Moreover, serum measurements of the IGF-I system could possibly provide further insight into stress fracture injury risk. Conclusions: Preliminary data3 suggest that circulating IGF-I system components are differentially expressed in females sustaining stress fractures during military BT. Additionally, data suggest that the bioavailable IGF-I response to strenuous exercise may differ in female recruits susceptible to stress fracture injury when compared to non-injured recruits. This suggests the possibility that increased susceptibility to stress fracture injury may be attributed to differences in the IGF-I system response to physical training (i.e., increased susceptibility to stress fracture may be due to a blunted bioavailable IGF-I response to training or increased basal levels of certain IGFBPs). However, the underlying mechanism for the differences in IGF-I system component concentrations between recruits sustaining stress fractures and uninjured counterparts is still unclear and warrants further investigation. References 1Nindl BC, Pierce JR. Insulin-like growth factors I as a biomarker of health, fitness, and training status. Med Sci Sports Exerc 2010; 42(1):39-49. https://doi.org/10.1249/mss.0b013e3181b07c4d 2Nindl BC, McClung JP, Miller JK, et al. Bioavailable IGF-I is associated with fat-free mass gains after physical training in women. Med Sci Sports Exerc 2011; 43(5):793-799. https://doi.org/10.1249/MSS.0b013e31820065.ea 3Strohbach CA, Scofield DE, Nindl BC, et al. Female recruits sustaining stress fractures during military basic training demonstrate differential concentrations of circulating IGF-I system components: a preliminary study. Growth Horm IGF Res 2012; 22(5):151-157. https://doi.org/10.1016/j.ghir.2012.04.007

Digital phenotyping in transmission constrained, military operational environments

Introduction: Stress fracture injuries affect defence forces worldwide. The sudden onset of high-impact exercise, insufficient recovery, and suboptimal conditions (e.g., energy and sleep restriction) elicit injuries in 5 to 10% of military recruits. Women are three times more likely to develop stress fractures than men1, and this risk of injury is projected to increase further in women employed in ground close combat roles2. Oestrogens have two distinct roles in women’s bone biology. 1. Oestrogens influence the size and shape of bone during puberty, promoting endosteal contraction, and resulting in a smaller cross-sectional area than men. A smaller bone size contributes to the increased risk of stress injuries under loading in women. 2. Oestrogens prevent excessive bone resorption by suppressing RANKL expression. Low oestrogen caused by suppression of the hypothalamic-pituitary-ovarian axis—indicated by a loss of menstrual periods—is highly prevalent during arduous exercise3 and demineralises bone. Cessation of menstrual periods, amenorrhoea, is a risk factor for stress fracture injury4. Ovulation is a key event in the menstrual cycle, preceded by a peak in oestrogen concentration, and followed by increased progesterone concentration. Anovulatory cycles are characterised by low, non-cyclical oestrogen and progesterone. Ovulation is a sign of menstrual health and informs women of their reproductive hormonal status. Non-invasive, innovative methods of detecting ovulation are disrupted approaches to mitigating injury risk in women. Methods: This presentation will provide an overview of the epidemiology of stress fracture injuries in military personnel, reporting the prevalence and patterns of injuries observed during basic military training. The role of the sex steroid hormones on bone health will be described, and the utility of wearables to detect ovulation appraised. Primary evidence will be obtained from open-source, peer-reviewed literature, and wearable data will be drawn from both published studies and preliminary data from the British Army’s EMPOWER study. Conclusions: A high proportion of women experience menstrual disturbances during arduous training and suffer a high incidence of stress fractures. The validity of wearable technology for women to detect ovulation during arduous military training, characterised by high physical demands, stress, and restricted energy and sleep, is under investigation. Acknowledgements: This work was funded by the British Army. References 1O’Leary TJ, Wardle SL, Rawcliff AJ, et al. Understanding the musculoskeletal injury risk of women in combat: the effect of infantry training and sex on musculoskeletal injury incidence during British Army basic training. BMJ Mil Health. 2020; 0:1-5. https://doi.org/10.1136/jramc-2019-001347 2Ministry of Defence. Women in Ground Close Combat Roles - Interim Health Report 2016. Available at: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/536381/20160706_ADR006101_Report_Women_in_Combat_WEB-FINAL.PDF Accessed 31 Aug 2021. 3Gifford RM, O’Leary TJ, Wardle SL, et al. Reproductive and metabolic adaptation to multistressor training in women. Am J Physiol Endoc-M 2021; 321(2):E281-E291. https://doi.org/10.1152/ajpendo.00019.2021 4Ackerman KE, Sokoloff NC, Maffazioli GDN, et al. Fractures in relation to menstrual status and bone parameters in young athletes. Med Sci Sports Exerc 2015; 47(8):1577-1586. https://doi.org/10.1249/MSS.0000000000000574

Molecular vital signs: wearable technologies for the real-time measurement of molecular markers of health and human performance

Introduction: Warfighters operate in complex and chaotic multi-stressor environments. Soldier interface with the external world on the battlefield impacts health and performance and is reflected through changes in internal physiology. Previous studies of operational stress using either cross-sectional or repeated measures designs have demonstrated substantial alterations in physiology including heightened hypothalamic-pituitary-adrenal axis (HPA) arousal, suppressed function of hypogonadal (HPG) and hypothalamic-pituitary-thyroid (HPT) axes, and increased immune system activation1. Responses of these systems are monitored and measured via biological analytes including, but not limited to, epinephrine, norepinephrine, adrenocorticotrophic hormone, cortisol, insulin-like growth factor-I, testosterone, thyroid hormones, and inflammatory cytokines2. However, interpretation of these results is complicated by pre-analytical factors such as collection timing, sample processing, nutrient intake, and hydration status. Therefore, we propose the implementation of continuous or real-time monitoring of biological fluids (e.g., saliva, blood, sweat) for actionable information regarding hydration, muscle status, inflammation, injury risk, and metabolic health that can be used for individualized recommendations and performance optimization. Application platforms and monitoring technologies for active and passive data collection have evolved to the point where holistic surveillance is becoming feasible. For example, continuous monitoring of hormones related to systemic anabolic/catabolic balance and inflammation can help enhance physical performance and minimize overtraining, respectively3,4. Future directions: Real-time, high-fidelity tracking of biomarkers across multiple biocompartments for the purposes of enhancing health, performance, and career longevity is a next critical step for optimizing soldier readiness, lethality, and survivability in combat. Future technologies will likely enable a wider range and more precise tracking of systemic signalling (e.g., multi-omics), leading to actionable information, at the individual level, for military leaders to use in training and combat. Soldier self-report input, however, will likely remain an important aspect for guiding practices. Real-time tracking may also reorient our perception of what is deemed most physiologically relevant for monitoring soldier performance. References 1Henning PC, Park B-S, Kim J-S. Physiological decrements during sustained military operational stress. Mil Med 2011; 176:991-997. https://doi.org/10.7205/MILMED-D-11-00053 2Lee EC, Fragala MS, Kavouras SA, et al. Biomarkers in sports and exercise: tracking health, performance, and recovery in athletes. J Strength Cond Res 2017; 31:2920-2937. https://doi.org/10.1519/JSC.0000000000002122 3Kraemer WJ, Ratamess NA, Nindl BC. Recovery responses of testosterone, growth hormone, and IGF-1 after resistance exercise. J App Physiol 2017; 122:549-558. https://doi.org/10.1152/japplphysiol.00599.2016 4Smith LL. Cytokine hypothesis of overtraining: a physiological adaptation to excessive stress? Med Sci Sports Exerc 2000; 32:317-331.

Blood volume versus deoxygenated NIRS signal: computational analysis of the effects muscle O2 delivery and blood volume on the NIRS signals.

Near-infrared spectroscopy (NIRS) signals quantify the oxygenated (ΔHbMbO2) and deoxygenated (ΔHHbMb) heme group concentrations. ΔHHbMb has been preferred to ΔHbMbO2 in evaluating skeletal muscle oxygen extraction because it is assumed to be less sensitive to blood volume (BV) changes, but uncertainties exist on this assumption. To analyze this assumption, a computational model of oxygen transport and metabolism is used to quantify the effect of O2 delivery and BV changes on the NIRS signals from a canine model of muscle oxidative metabolism (Sun Y, Ferguson BS, Rogatzki MJ, McDonald JR, Gladden LB. Med Sci Sports Exerc 48: 2013-2020, 2016). The computational analysis accounts for microvascular (ΔHbO2, ΔHHb) and extravascular (ΔMbO2, ΔHMb) oxygenated and deoxygenated forms. Simulations predicted muscle oxygen uptake and NIRS signal changes well for blood flows ranging from resting to contracting muscle. Additional NIRS signal simulations were obtained in the absence or presence of BV changes corresponding to a heme groups concentration changes (ΔHbMb = 0-48 µM). Under normal delivery (Q = 1.0 L·kg-1·min-1) in contracting muscle, capillary oxygen saturation (So2) was 62% with capillary ΔHbO2 and ΔHHb of ± 41 µΜ for ΔHbMb = 0. An increase of BV (ΔHbMb = 24 µΜ) caused a ΔHbO2 decrease (16µΜ) almost twice as much as the increase observed for ΔHHb (9 µΜ). When So2 increased to more than 80%, only ΔHbO2 was significantly affected by BV changes. The analysis indicates that microvascular So2 is a key factor in determining the sensitivity of ΔHbMbO2 and deoxygenated ΔHHbMb to BV changes. Contrary to a common assumption, the ΔHHbMb is affected by BV changes in normal contracting muscle and even more in the presence of impaired O2 delivery.NEW & NOTEWORTHY Deoxygenated is preferred to the oxygenated near-infrared spectroscopy signal in evaluating skeletal muscle oxygen extraction because it is assumed to be insensitive to blood volume changes. The quantitative analysis proposed in this study indicates that even in absence of skin blood flow effects, both NIRS signals in presence of either normal or reduced oxygen delivery are affected by blood volume changes. These changes should be considered to properly quantify muscle oxygen extraction by NIRS methods.

Commentaries on Viewpoint: Fragile bones of elite cyclists: to treat or not to treat?

Commentaries on Viewpoint: Fragile bones of elite cyclists: to treat or not to treat?

Effects of Weekly Interval Training at High Intensity interval training on Dynamic Cardiorespiratory Responses to Exercise

Purpose Previously we reported that high-intensity interval training (HIIT) at 80% maximal work-rate (WRmax), even when performed at a low frequency of once a week, markedly improves maximal cardiorespiratory function and maximal performance time (Med Sci Sports Exerc. 2015). However, it has not been determined whether more intense interval exercise training will have the similar effect on maximal oxygen uptake (VO2max) or alter the dynamics of the cardiorespiratory response during maximal exercise. The purpose of this study was to examine whether or not the same effect can be obtained, even with HIIT at 95%WRmax for 8 weeks which further increased exercise intensity than the previous study. Methods Seventeen healthy male college students were randomly assigned to one of the two following groups; high-intensity interval training group (HIT; n = 9) and control group (n = 8). HIT group performed the training on a cycle ergometer once a week for 8 weeks. The training was consisted of three bouts until volitional fatigue at 95%WRmax. Cardiorespiratory function during maximal ramp and step (high-intensity) exercise test was investigated before and after the intervention period. Results The training resulted in increased VO2max (+9%, p = 0.037), maximal heart rate (+4%, p = 0.023) and maximal minute ventilation (+19%, p = 0.007) during maximal ramp test, respectively. Significant changes in the dynamic response of heart rate and blood pressure at the onset of high-intensity exercise were observed after the training program compared with baseline, and improvement in exhaustion time was also observed (+ 93%, P < 0.001). In addition, increased left ventricular posterior wall thickness at rest was also observed after training (+12%, p = 0.004). Conclusion The present results indicate that more intense HIIT performed at a low frequency once a week not only increased maximal cardiorespiratory function and exercise performance, but also induced cardiovascular adaptation in the enhancement of heart rate and blood pressure response during step exercise, as well as induces cardiac morphological adaptations involving left ventricular hypertrophy, as we have already found in previous studies.

Commentaries on Viewpoint: The interaction between SARS-CoV-2 and ACE2 may have consequences for skeletal muscle viral susceptibility and myopathies.

Commentaries on Viewpoint: The interaction between SARS-CoV-2 and ACE2 may have consequences for skeletal muscle viral susceptibility and myopathies.

On the Gravity-Driven Sliding Motion of a Planar Board on a Tilted Soft Porous Layer

In this paper, we report a novel experimental study to investigate the gravity-driven sliding motion of a planar board over a tilted soft porous layer. A laser displacement sensor was used to measure the motion of the board, while a high-speed camera was adopted to capture the detailed compression of the porous layer when the board glided over it. The pore pressure generation, as a result of the compression, was recorded by pressure sensors mounted on the bottom surface of the porous layer. One finds that, the pressure distribution agrees well with the theory developed by Wu and Sun (Med Sci Sports Exerc 43:1955–1963, 2011). Extensive parametric study was performed by varying the center of gravity of the planar board, the tilted angle and the porous material. Consistent agreement between the theoretical predictions and experimental results was obtained. It shows that, the effect of soft porous lubrication is enhanced when the center of gravity moves toward to the trailing edge of the planar board, or the tilted angle of the porous layer is increased, or a smoother fibrous surface is used.

Individualized exercise and the health of the AYA cancer survivor population

Background + Hypothesis&#x0D; Adolescent and young adult cancer survivors (AYACS: ages 15-39) have an 84.5% five-year survival rate.(1) AYACS have a 10 times greater risk to develop cardiac disease compared to healthy peers.(2) This is in part due to their lower physical activity.(3) Structured exercise in adult cancer survivors improves strength, fatigue, VO2, and antioxidant levels and it decreases markers of cellular damage(4, 5). AYACS could benefit similarly, reducing long-term health effects. Although evidence suggests exercise is beneficial in older cancer survivors, this has not been demonstrated in AYACS. We hypothesized that a 12-week one-on-one multi-modal, community-based exercise program would improve AYACS outcomes compared to baseline or inactive AYACS. The current study hopes to demonstrate the feasability of an exercise intervention in a community setting within Indianapolis.&#x0D; Methods&#x0D; Six individuals were included in a feasibility trial for a larger pilot study of 374 participants. On day 1, baseline assessments were performed for experimental outcomes: body composition, strength, flexibility, VO2peak, balance, plasma biomarkers, PA, psychological health, health-related quality of life, and fatigue. Mini reassessments were performed at week 5, measuring strength and VO2peak with an estimated 1-rep maximum and 6-minute Walk Test respectively; in the larger pilot study participants will be reassessed at weeks 12 and 24. Participants train for 60 minutes (20 cardio, 30 weights, 10 stretching) 3 times a week for 12 weeks, one-on-one with a cancer exercise specialist.&#x0D; Results&#x0D; The average change in VO2peak was +25.3% and in strength was +17.5% (no statistical analysis). Adherence was 90.9%.&#x0D; Conclusion + Potential impact&#x0D; This trial suggests the feasibility of a pilot larger study. The greatest limitation was that the population sample was not within the AYACS age range. However, as the goal was to show feasibility rather than to prove efficacy, the sample gave useful information.&#x0D; Sources (1-5) 1. Anderson C, Smitherman AB, Nichols HB. Conditional relative survival among long-term survivors of adolescent and young adult cancers. Cancer. 2018;124(14):3037-43. 2. Armstrong GT, Kawashima T, Leisenring W, Stratton K, Stovall M, Hudson MM, et al. Aging and risk of severe, disabling, life-threatening, and fatal events in the childhood cancer survivor study. J Clin Oncol. 2014;32(12):1218-27. 3. Wu YP, Yi J, McClellan J, Kim J, Tian T, Grahmann B, et al. Barriers and Facilitators of Healthy Diet and Exercise Among Adolescent and Young Adult Cancer Survivors: Implications for Behavioral Interventions. J Adolesc Young Adult Oncol. 2015;4(4):184-91. 4. Repka CP, Hayward R. Oxidative Stress and Fitness Changes in Cancer Patients after Exercise Training. Med Sci Sports Exerc. 2016;48(4):607-14. 5. Repka CP, Hayward R. Effects of an Exercise Intervention on Cancer-Related Fatigue and Its Relationship to Markers of Oxidative Stress. Integr Cancer Ther. 2018;17(2):503-10.

Increased Female Athlete Triad Knowledge Following a Brief Video Educational Intervention

To assess female high school athletes’ changes in Female Athlete Triad (Triad) knowledge following a brief educational intervention.Triad knowledge questionnaires were completed by female high school athletes before and after either an educational video intervention or control group activities.Four high schools in the Pacific Northwest.Ninety-three female high school athletes (15.9±1.2 years) participating in basketball, cheerleading, track & field, softball, soccer, golf, tennis, and volleyball.The 10-minute Social Cognitive Theory-based educational video highlighted Triad etiology, progression, impact on sports performance, and fueling strategies to decrease Triad risk.Triad knowledge score out of 7; proportion of participants who correctly answered each question.Mann-Whitney U tests assessed differences in pre and post intervention Triad knowledge scores between the control and intervention group. The McNemar test compared the proportion of participants (intervention group) who correctly answered individual Triad knowledge questions pre vs. post-intervention.Participants in the intervention group achieved greater increases in Triad knowledge following the intervention, than did control participants (P<0.001). For each Triad question, improvements in the proportion of participants (intervention group) who answered correctly was observed (P<0.05).The Triad educational video was an effective and timeefficient method for increasing Triad knowledge among female high school athletes.

\u201cAs du Coeur\u201d study: a randomized controlled trial on physical activity maintenance in cardiovascular patients

BackgroundThe benefits of supervised physical activity programs in cardiac rehabilitation have been amply demonstrated, but the quantity of physical activity often declines quickly once supervision ends. This trial assesses the effectiveness of an experimental intervention drawing on habit formation theory to maintain physical activity.MethodsCardiovascular patients (N = 47) were randomly assigned to one of two groups. The first group participated in two supervised physical activity (SPA) sessions per week for 20 weeks. The second group was offered a progressively autonomous physical activity (PAPA) program as follows: the same supervised program as the SPA group for 10 weeks and then a further 10 weeks with one supervised session replaced by a strategy to build and sustain the habit of autonomous physical activity. The International Physical Activity Questionnaire (IPAQ; Craig et al. Med Sci Sports Exerc 35(8):1381–1395, 2003) was used to measure the quantity of physical activity, which was the primary outcome. The number of participants was limited, and we thus took multiple IPAQ measurements (at 0, 5, 7, 9 and 12 months after the start of the intervention) and used a mixed model for analysis. Physical condition, automaticity of the physical activity behavior, motivation, and quality of life were examined for changes.ResultsNo significant between-group differences were noted for physical activity behaviors after the program, physical condition, motivation, or behavioral automaticity. The PAPA group nevertheless completed more PA sessions during the intervention, and their quality of life was significantly higher than that of the SPA group at 12 months.ConclusionAlthough the number of supervised sessions was lower, the progressively autonomous PA program resulted in the same or even higher positive outcomes than the fully supervised PA program.Trial registrationCurrent Controlled Trials ISRCTN77313697, retrospectively registered on 20 November 2015.

Virtual reality as a countermeasure for physical training in bed rest and artificial gravity conditions.

Virtual reality as a countermeasure for physical training in bed rest and artificial gravity conditions.

Resistance training and exercise tolerance during high-intensity exercise: moving beyond just running economy and muscle strength.

Resistance training and exercise tolerance during high-intensity exercise: moving beyond just running economy and muscle strength.

Principles, insights, and potential pitfalls of the noninvasive determination of muscle oxidative capacity by near-infrared spectroscopy.

Skeletal muscle oxidative capacity is highly plastic, strongly associated with whole-body aerobic capacity (16, 18) and state of health. Loss of muscle oxidative capacity is associated with physical inactivity, aging and chronic disease (17), and has been implicated in the pathophysiology of obesity and diabetes (21). Evaluating these changes has traditionally been limited to invasive or costly assessments (biopsy or ³¹P MRS). To address this, Hamaoka and colleagues developed an innovative, non-invasive approach using near-infrared spectroscopy (NIRS) to quantitatively measure muscle oxygen consumption (mVO₂; 12) and use this to infer muscle oxidative capacity based on the mVO₂ recovery rate constant (k) (23; later modified 26). This technique has been subsequently used to interpret relative differences in oxidative capacity across a wide range of muscles, ages and disease states (Figure 1C). The purpose of this Viewpoint is to open a discussion on the principles, insights and potential pitfalls of using NIRS to measure k and infer muscle oxidative capacity.

Going green for mental health

British Journal of Neuroscience NursingVol. 13, No. 1 CommentsGoing green for mental healthGeorge WinterGeorge WinterSearch for more papers by this authorGeorge WinterPublished Online:28 Feb 2017https://doi.org/10.12968/bjnn.2017.13.1.41AboutSectionsView articleView Full TextPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareShare onFacebookTwitterLinked InEmail View article References Barton J, Rogerson M, Pretty J et al. (2016) Green Exercise Research Team. http://tinyurl.com/zngm59a (accessed 9 January 2017) Google ScholarCohen-Cline H, Turkheimer E, Duncan GE (2015) Access to green space, physical activity and mental health. J Epidemiol Community Health 69(6): 523–9 Google ScholarMcEachan RRC, Prady SL, Smith G et al. (2015) The association between green space and depressive symptoms in pregnant women: moderating roles of socioeconomic status and physical activity. Epidemiol Community Health 70(3): 253–9 Google ScholarMurray AD, Daines L, Archibald D et al. (2016) The relationships between golf and health: a scoping review. Br J Sports Med Epub ahead of print Crossref, Google ScholarRogerson M, Gladwell VF, Gallagher DJ et al. (2016) Influences of green outdoors versus indoors environmental settings on psychological and social outcomes of controlled exercise. Int J Environ Res Publ Health 13(4): 363 Crossref, Google ScholarRousseau J (1782) The Confessions [1953 edn. translated by JM Cohen]. Penguin, London: 382 Google ScholarWilliams PT (2014) Reduced risk of brain cancer mortality from walking and running. Med Sci Sports Exerc 46(5): 927−32 Crossref, Google Scholar FiguresReferencesRelatedDetails 2 February 2017Volume 13Issue 1ISSN (print): 1747-0307ISSN (online): 2052-2800 Metrics History Published online 28 February 2017 Published in print 2 February 2017 Information© MA Healthcare LimitedPDF download

Physical activity—time to take it seriously and regularly

Physical activity—time to take it seriously and regularly