Genotypic Variations Associated with Changes in Body Mass in Response to Endurance Training.

This study investigates the extent to which different genotypes can explain changes in body mass following an 8-week running program, in a UK population. Participants were randomly assigned to either a training (n = 17) or control group (n = 21). Participants' diets were not altered, only the exercise regime was manipulated to isolate effects. The exercise group completed a periodized running program consisting of 20-30 min, over an agreed route, three times per-week, whilst the control groups refrained from daily exercise. Participants were screened at the end of the study for 1,000 gene variants using a DNA test kit. Results demonstrated a significant reduction in body mass, within the exercise, compared to the control group (p = .002). This reduction in body mass varied significantly (p = .024) between individuals within the exercise group. Moreover, genetic analysis identified 17 single nucleotide polymorphisms (SNPs) associated with this variation (r2 = .74; p < .001). These findings indicate that individuals with specific alleles are better predisposed to weight-management, compared to their counterparts, following an exercise program. This study helps to bridge the gap between population health and exercise science and can inform research in the application of genetics to help develop individually tailored health interventions.

Words matter: Effects of instructional cues on pressure pain threshold values in healthy people.

BACKGROUND: Pressure pain threshold (PPT) measurements require standardised verbal instructional cues to ensure that the increasing pressure is stopped at the correct time consistently. This study aimed to compare how PPT values and their test-retest reliability were affected by different instructional cues. METHODS: At two separate sessions, two PPT measurements were taken at the anterior knee for each of four different instructional cues: the cue of the German Neuropathic Research Network instructions ('DFNS'), the point where pressure first feels uncomfortable ('Uncomfortable'), 3/10 on the numerical pain rating scale ('3NPRS'), and where pain relates to an image from the pictorial-enhanced NPRS scale ('Pictorial'). Linear mixed modeling was used to quantify differences between pairs of instructional cues. Test-retest reliability was estimated using intraclass correlation coefficients (ICC[2,1] and ICC[2,k]). RESULTS: Twenty participants were recruited. The cue resulting in greatest PPT value was DFNS (394.32 kPa, 95%CI [286.32 to 543.06]), followed by Pictorial (342.49 kPa, 95%CI [248.68 to 471.68]), then Uncomfortable (311.85 kPa, 95%CI [226.43 to 429.48]), and lastly 3NPRS (289.78 kPa, 95%CI [210.41 to 399.09]). Five of six pairwise contrasts were statistically significant. Regardless of the cues, the point estimates of ICC (2,1) ranged from 0.80 to 0.86, and the ICC (2,k) values ranged from 0.89 to 0.93. No statistically significant differences were found between any pairwise contrasts of reliability indices. CONCLUSION: Words matter when instructing people when to stop testing in pressure algometry. Clinicians should use the same instructional cue when assessing pain thresholds to ensure reliability.

Four-year longitudinal associations of physical activity, waist circumference, and blood pressure in UK adolescents.

BACKGROUND: This study assessed the specific influence of physical activity (PA) and waist circumference (WC) on the 4-year growth trajectory of blood pressure in UK high-school students. METHODS: Four-year longitudinal monitoring of 1501 adolescents was conducted as part of the EoEHHS. Measurements were taken in Grades (G)7, 9, and 11. RESULTS: Systolic (SBP) and diastolic blood pressure (DBP) increased over the 4-year period (SBP G7 114.6 ± 8.9 mmHg, G9 118.1 ± 9.7 mmHg, G11 122.8 ± 7.8 mmHg; DBP G7 66.7 ± 6.6 mmHg, G9 68.0 ± 6.4 mmHg, G11 70.0 ± 5.2 mmHg). Baseline WC predicted baseline and growth in SBP, but the strongest contribution to SBP came from changes in WC (ß = 0.084, p = 0.002). Baseline PAQ-A score (ß = -0.822, p = 0.020) and changes in PAQ-A score (ß = -0.650, p = 0.019) were associated with smaller increases in DBP over the 4-year measurement period. CONCLUSIONS: Baseline and change in WC predicted the growth trajectory of SBP, while baseline and change in PA predicted the growth trajectory of DBP. PA and WC have a prognostic value in predicting changes in blood pressure in adolescents. Increasing PA during adolescence could slow the rise in DBP over time. This is meaningful for future hypertension and CVD risk reduction into adulthood. IMPACT: Hypertension in adolescents is a growing health problem that is often overlooked. Baseline and changes in waist circumference over a 4-year period predicted development of systolic blood pressure, while baseline and changes in physical activity predicted development of diastolic blood pressure. Physical activity and waist circumference have a prognostic value in predicting changes in blood pressure in adolescents and could be valuable in planning programmes to prevent hypertension in similar communities and reduce the risk of future adult hypertension.

Cold-Water Immersion and Lower Limb Muscle Oxygen Consumption as Measured by Near-Infrared Spectroscopy in Trained Endurance Athletes.

CONTEXT: Cold-water immersion (CWI) has been reported to reduce tissue metabolism postimmersion, but physiological data are lacking regarding the muscle metabolic response to its application. Near-infrared spectroscopy (NIRS) is a noninvasive optical technique that can inform muscle hemodynamics and tissue metabolism. OBJECTIVE: To investigate the effects of CWI at 2 water temperatures (10°C and 15°C) on NIRS-calculated measurements of muscle oxygen consumption (mVO2). DESIGN: Crossover study. SETTING: University sports rehabilitation center. PATIENTS OR OTHER PARTICIPANTS: A total of 11 male National Collegiate Athletic Association Division II long-distance runners (age = 23.4 ± 3.4 years, height = 1.8 ± 0.1 m, mass = 68.8 ± 10.7 kg, mean adipose tissue thickness = 6.7 ± 2.7 mm). INTERVENTION(S): Cold-water immersion at 10°C and 15°C for 20 minutes. MAIN OUTCOME MEASURE(S): We calculated mVO2 preimmersion and postimmersion at water temperatures of 10°C and 15°C. Changes in tissue oxyhemoglobin (O2Hb), deoxyhemoglobin (HHb), total hemoglobin (tHb), hemoglobin difference (Hbdiff), and tissue saturation index (TSI %) were measured during the 20-minute immersion at both temperatures. RESULTS: We observed a decrease in mVO2 after immersion at both 10°C and 15°C (F1,9 = 27.7801, P = .001). During the 20-minute immersion at both temperatures, we noted a main effect of time for O2Hb (F3,27 = 14.227, P = .001), HHb (F3,27 = 5.749, P = .009), tHb (F3,27 = 24.786, P = .001), and Hbdiff (F3,27 = 3.894, P = .020), in which values decreased over the course of immersion. Post hoc pairwise comparisons showed that these changes occurred within the final 5 minutes of immersion for tHb and O2Hb. CONCLUSIONS: A 20-minute CWI at 10°C and 15°C led to a reduction in mVO2. This was greater after immersion at 10°C. The reduction in mVO2 suggests a decrease in muscle metabolic activity (ie, O2 use after CWI). Calculating mVO2 via the NIRS-occlusion technique may offer further insight into muscle metabolic responses beyond what is attainable from observing the NIRS primary signals.

A cross-sectional investigation of back pain beliefs and fear in physiotherapy and sport undergraduate students.

BACKGROUND: Although low back pain (LBP) beliefs have been well investigated in mainstream healthcare discipline students, the beliefs within sports-related study students, such as Sport and Exercise Science (SES), Sports Therapy (ST), and Sport Performance and Coaching (SPC) programmes have yet to be explored. This study aims to understand any differences in the beliefs and fear associated with movement in students enrolled in four undergraduate study programmes-physiotherapy (PT), ST, SES, and SPC. METHOD: 136 undergraduate students completed an online survey. All participants completed the Tampa Scale of Kinesiophobia (TSK) and Back Beliefs Questionnaire (BBQ). Two sets of two-way between-subjects Analysis of Variance (ANOVA) were conducted for each outcome of TSK and BBQ, with the independent variables of the study programme, study year (1st, 2nd, 3rd), and their interaction. RESULTS: There was a significant interaction between study programme and year for TSK (F(6, 124) = 4.90, P < 0.001) and BBQ (F(6, 124) = 8.18, P < 0.001). Post-hoc analysis revealed that both PT and ST students had lower TSK and higher BBQ scores than SES and SPC students particularly in the 3rd year. CONCLUSIONS: The beliefs of clinicians and trainers managing LBP are known to transfer to patients, and more negative beliefs have been associated with greater disability. This is the first study to understand the beliefs about back pain in various sports study programmes, which is timely, given that the management of injured athletes typically involves a multidisciplinary team.

Obese individuals do not underreport dietary intake to a greater extent than nonobese individuals when data are allometrically-scaled.

OBJECTIVE: The aim of this study was to assess the extent of misreporting in obese and nonobese adults on an absolute, ratio-scaled, and allometrically-scaled basis. METHOD: Self-reported daily energy intake (EI) was compared with total energy expenditure (TEE) in 221 adults (106 male, 115 female; age 53 ± 17 years, stature 1.68 ± 0.09 m, mass 79.8 ± 17.2 kg) who participated in a doubly-labeled water (DLW) subsection of 2013-2015 National Diet and Nutrition Survey. Data were log transformed and expressed as absolute values, according to simple ratio-standards (per kg body mass) and adjusted for body mass allometrically. Absolute and ratio-scaled misreporting were examined using full-factorial General Linear Models with repeated measures of the natural logarithms of TEE or EI as the within-subjects factor. The natural logarithm of body mass was included as a covariate in the allometric method. The categorical variables of gender, age, obesity, and physical activity level (PAL) were the between-factor variables. RESULTS: On an absolute-basis, self-reported EI (2759 ± 590 kcal·d-1 ) was significantly lower than TEE measured by DLW (2759 ± 590 kcal·d-1 : F1,205  = 598.81, p < .001, ηp 2 =0.75). We identified significantly greater underreporting in individuals with an obese BMI (F1,205  = 29.01, p <.001, ηp 2 =0.12), in more active individuals (PAL > 1.75; F1,205  = 34.15, p <.001, ηp 2 =0.14) and in younger individuals (≤55 years; F1,205  = 14.82, p < .001, ηp 2 =0.07), which are all categories with higher energy needs. Ratio-scaling data reduced the effect sizes. Allometric-scaling removed the effect of body mass (F1,205 =0.02, p = 0.887, ηp 2 =0.00). CONCLUSION: In weight-stable adults, obese individuals do not underreport dietary intake to a greater extent than nonobese individuals. These results contradict previous research demonstrating that obesity is associated with a greater degree of underreporting.

German volume training for health promotion: Acute vasopressor, pulmonary and metabolic responses.

Resistance training (RT) is increasingly recommended for incorporation into comprehensive fitness or "exercise as medicine" programs. However, the acute effects of RT, and especially its different sub-types, and how they impact health outcomes are not fully investigated. This study evaluated German Volume Training (GVT) ("10 set × 10 rep scheme") for its efficacy for its use in health settings. This study utilized a randomized crossover design with subjects serving as their own controls to establish baseline values. Subjects were blinded to the study hypothesis. Subjects performed a single session of GVT or no exercise, in a randomised order separated by a 1-week washout period. Outcomes were assessed before and immediately post-exercise. GVT significantly (p < 0.05) decreased systolic blood pressure (SBP), diastolic blood pressure (DBP) and mean arterial pressure (MAP), but increased heart rate (HR), rate pressure product (RPP) and rating of perceived exertion (RPE). No changes were found in the measured spirometry parameters. Increases were observed in carbon dioxide production (VCO2) and minute ventilation (VE), but not respiratory exchange ratio. Post hoc analysis demonstrated that post-GVT values were significantly lower for SBP (p = 0.017; d = 1.00), DBP (p = 0.013; d = 0.90), MAP (p = 0.024; d = 1.06), and VCO2 (p = 0.009; d = -1.32), and significantly higher for RPP (p = 0.001; d = -3.11), RPE (p = 0.001; d = -14.14), and HR (p = 0.001; d = -3.00). This study indicates that acute GVT promotes post-exercise hypotension and is of sufficient intensity to increase both objective HR and subjective RPE intensities appropriately for use in a variety of health promotion settings.

The associations between physical activity intensity, cardiorespiratory fitness, and non-alcoholic fatty liver disease.

BACKGROUND AND AIM: High levels of physical activity and cardiorespiratory fitness may protect against non-alcoholic fatty liver disease. We investigated whether different physical activity intensities and cardiorespiratory fitness were independent predictors of non-alcoholic fatty liver disease. METHODS: We included healthy adults with no prior diagnosis of liver dysfunction. Non-alcoholic fatty liver disease prevalence was estimated based on fatty liver index scores. We created tertiles of self-reported low, moderate, and vigorous physical activity. Participants completed an incremental treadmill test to estimate cardiorespiratory fitness, and data were subsequently separated into quintile groups (Q1 [least fit] through Q5 [most fit]). RESULTS: Non-alcoholic fatty liver disease prevalence in our sample of 7111 adults was 28.3% in male adults and 6.5% in female adults. Logistic regression showed the relative odds of non-alcoholic fatty liver disease were 42% lower if > 60 min/week of vigorous physical activity was maintained (odds ratio [OR] = 0.58, confidence interval [CI]: 0.49-0.68). There was a negative dose-response association between cardiorespiratory fitness and non-alcoholic fatty liver disease between Q1 and Q4. Compared with Q1, odds were 39% (OR = 0.61, CI: 0.51-0.73) lower in Q2, through to 51% lower in Q5 (OR = 0.49, CI: 0.41-0.60). Moderate physical activity did not reduce the odds of non-alcoholic liver disease. CONCLUSIONS: We found the lowest prevalence of non-alcoholic fatty liver disease in adults achieving > 60 min/week of vigorous physical activity. However, a stronger dose-response relationship existed between cardiorespiratory fitness and non-alcoholic fatty liver disease. Improving cardiorespiratory fitness as a potential therapeutic target for treatment and prevention of non-alcoholic fatty liver disease warrants further investigation.

Perception of Carbohydrate Availability Augments High-Intensity Intermittent Exercise Capacity Under Sleep-Low, Train-Low Conditions.

The authors tested the hypothesis that perception of carbohydrate (CHO) availability augments exercise capacity in conditions of reduced CHO availability. Nine males completed a sleep-low train model comprising evening glycogen-depleting cycling followed by an exhaustive cycling protocol the next morning in the fasted state (30 min steady state at 95% lactate threshold followed by 1-min intervals at 80% peak power output until exhaustion). After the evening depletion protocol and prior to sleeping, subjects consumed (a) a known CHO intake of 6 g/kg body mass (TRAIN HIGH) or (b) a perceived comparable CHO intake but 0 g/kg body mass (PERCEPTION) or a known train-low condition of 0 g/kg body mass (TRAIN LOW). The TRAIN HIGH and PERCEPTION trials were conducted double blind. During steady state, average blood glucose and CHO oxidation were significantly higher in TRAIN HIGH (4.01 ± 0.56 mmol/L; 2.17 ± 0.70 g/min) versus both PERCEPTION (3.30 ± 0.57 mmol/L; 1.69 ± 0.64 g/min, p < .05) and TRAIN LOW (3.41 ± 0.74 mmol/L; 1.61 ± 0.59 g/min, p < .05). Exercise capacity was significantly different between all pairwise comparisons (p < .05), where TRAIN LOW (8 ± 8 min) < PERCEPTION (12 ± 6 min) < TRAIN HIGH (22 ± 9 min). Data demonstrate that perception of CHO availability augments high-intensity intermittent exercise capacity under sleep-low, train-low conditions, though this perception does not restore exercise capacity to that of CHO consumption. Such data have methodological implications for future research designs and may also have practical applications for athletes who deliberately practice elements of training in CHO-restricted states.