Clinical foot measurements as a proxy for plantar pressure testing in people with diabetes.

BACKGROUND: High plantar pressures are associated with increased foot ulcer risk in people with diabetes. Identification of high plantar pressures in people with diabetes is clinically challenging due to time and cost constraints of plantar pressure testing. Factors affecting foot biomechanics, including reduced joint range of motion and foot deformity, are implicated in the development of high plantar pressures and may provide a method to clinically identify those at risk of pressure related complications. The aim of this study was to investigate the contribution of joint range of motion and foot deformity measures on plantar pressures in a community dwelling group with diabetes. METHODS: Barefoot (Tekscan HR Mat™) and in-shoe (Novel Pedar-X®) plantar pressure variables, weight bearing ankle dorsiflexion, hallux range of motion, lesser toe deformities and hallux abductus (HAV) scale were assessed in 136 adults with diabetes (52.2% male; mean age 68.4 years). Multivariate multiple linear regression was used to assess the effect of the four biomechanical factors plus neuropathy and body mass index on plantar pressure variables. Non-parametric bootstrapping was employed to determine the difference in plantar pressure variables for participants with two or more foot biomechanical pathologies compared to those with less than two pathologies. RESULTS: Almost one third (32%) of the cohort had two or more foot biomechanical pathologies. Participants with two or more foot biomechanical pathologies displayed significant increases in all barefoot plantar pressure regions (except forefoot), compared to those with less than two pathologies. No significant changes were found for the in-shoe plantar pressure variables. The regression model explains between 9.9% (95%CI: 8.4 to 11.4%) and 29.6% (95% CI: 28.2 to 31%), and between 2.5% (1.0 to 4.0%) and 43.8% (95% CI: 42.5-44.9%), of the variance in the barefoot and in-shoe plantar pressure variables respectively. CONCLUSIONS: Participants presenting with two or more factors affecting foot biomechanics displayed higher peak pressures and pressure time integrals in all foot regions compared to those with less than two factors. The tests used in this study could help clinicians detect elevated plantar pressures in people with diabetes and present an opportunity for early preventative interventions.

Does a weight bearing equinus affect plantar pressure differently in older people with and without diabetes? A case control study.

BACKGROUND: A weight bearing ankle equinus has adverse effects on forefoot plantar pressure variables in older adults with diabetes, but it is unclear if this is also the case in older adults without diabetes. METHODS: 40 older adults with diabetes (88% type 2, mean diabetes duration 17.6 ± 14.8 years) and 40 older adults without diabetes, matched for age (±3 years), sex and BMI (±2 BMI units) were included (63% female, mean age 72 ± 4 years, BMI 30 ± 4 kg/m2). Primary outcomes were prevalence of a weight bearing equinus and evaluation of barefoot forefoot plantar pressures in older adults with and without diabetes. FINDINGS: A weight bearing equinus was present in 37.5% and 27.5% of the diabetes and non-diabetes group respectively with no significant difference between groups (p = 0.470). People with diabetes and equinus displayed higher peak pressure (808 versus 540 kPa, p = 0.065) and significantly higher pressure-time integral (86 versus 68 kPa/s, p = 0.030) than people with diabetes and no equinus group. The non-diabetes equinus group had significantly higher peak pressure (665 versus 567 kPa, p = 0.035) than those with no diabetes and no equinus, but no difference in pressure-time integral. INTERPRETATION: A high prevalence of a weight bearing equinus was detected in older adults with and without diabetes, with associated increases in plantar pressures. As an equinus has been associated with many foot pathologies this study's findings suggest that clinicians should check for the presence of a weight bearing ankle equinus in all older adults.

Degree of adiposity and obesity severity is associated with cutaneous microvascular dysfunction in type 2 diabetes.

BACKGROUNDS AND AIMS: Obesity and diabetes independently contribute to cutaneous microvascular dysfunction via pathological processes that are not fully understood. We sought to determine if obesity severity is associated with cutaneous microvascular dysfunction and measures of peripheral arterial disease in adults with type 2 diabetes in cross-sectional observational study design. METHODS AND RESULTS: Primary outcomes were post-occlusive reactive hyperaemia as determined by laser-Doppler fluxmetry (peak flux post-occlusion, time to peak flux post-occlusion, peak as a percentage of baseline, and area under the curve [AuC] index post-occlusion to pre-occlusion). Secondary outcomes were ankle- and toe-brachial indices (ABI and TBI) and systolic toe pressure. Thirty-six participants (20 men, 16 women) with mean age 55 ± 8 years, BMI of 36 ± 5 kg/m2 and duration of diabetes 8 ± 6 years underwent measurements. After adjusting for age and duration of diabetes, SAT and total percentage body fat were able to explain 29% (p = 0.001) and 20% (p = 0.01) of variance of AuC index models, as well as 29% (p = 0.02) and 18% (p = 0.02) of peak as a percentage of baseline models, respectively. Though TBI demonstrated moderate, significant correlations with SAT (r:0.37, p = 0.04) and total percentage body fat (r:0.39, p = 0.03), these were not upheld by regression analyses. Neither ABI nor systolic toe pressure significantly correlated with any measure of adiposity or obesity. CONCLUSION: These findings demonstrate impairment in cutaneous microvascular function related to adiposity and obesity severity in adults with type 2 diabetes, suggesting that obesity may pathologically effect cutaneous microvascular function in the absence of overt macrovascular disease, warranting further investigation.

The Effect of a Novel Low-Volume Aerobic Exercise Intervention on Liver Fat in Type 2 Diabetes: A Randomized Controlled Trial.

OBJECTIVE: The aim of this study was to examine the effect of a novel low-volume high-intensity interval training (HIIT), moderate-intensity continuous training (MICT), or placebo (PLA) intervention on liver fat, glycemia, and cardiorespiratory fitness using a randomized placebo-controlled design. RESEARCH DESIGN AND METHODS: Thirty-five inactive adults (age 54.6 ± 1.4 years, 54% male; BMI 35.9 ± 0.9 kg/m2) with obesity and type 2 diabetes were randomized to 12 weeks of supervised MICT (n = 12) at 60% VO2peak for 45 min, 3 days/week; HIIT (n = 12) at 90% VO2peak for 4 min, 3 days/week; or PLA (n = 11). Liver fat percentage was quantified through proton MRS. RESULTS: Liver fat reduced in MICT (-0.9 ± 0.7%) and HIIT (-1.7 ± 1.1%) but increased in PLA (1.2 ± 0.5%) (P = 0.046). HbA1c improved in MICT (-0.3 ± 0.3%) and HIIT (-0.3 ± 0.3%) but not in PLA (0.5 ± 0.2%) (P = 0.014). Cardiorespiratory fitness improved in MICT (2.3 ± 1.2 mL/kg/min) and HIIT (1.1 ± 0.5 mL/kg/min) but not in PLA (-1.5 ± 0.9 mL/kg/min) (P = 0.006). CONCLUSIONS: MICT or a low-volume HIIT approach involving 12 min of weekly high-intensity aerobic exercise may improve liver fat, glycemia, and cardiorespiratory fitness in people with type 2 diabetes in the absence of weight loss. Further studies are required to elucidate the relationship between exercise-induced reductions in liver fat and improvements in glycemia.

The effect of low-volume high-intensity interval training on cardiovascular health outcomes in type 2 diabetes: A randomised controlled trial.

BACKGROUND: Low-volume high-intensity interval training (HIIT) may be a time-efficient strategy that leads to similar or superior improvements in cardiorespiratory fitness (CRF) and cardiovascular disease (CVD) risk factors when compared with moderate-intensity continuous training (MICT). Our study investigated the effect of low-volume HIIT or MICT versus sham placebo-control (PLA) on central arterial stiffness, hemodynamic responses, and CVD risk factors in adults with obesity and type 2 diabetes (T2D). METHODS: Eligible participants were previously inactive adults with obesity and T2D. Individuals were randomly allocated to: i) HIIT (1 × 4 min cycling at 90% peak oxygen consumption [V̇O2peak]); ii) MICT (45 min of cycling at 60% VO2peak); or PLA. Training groups exercised thrice weekly for 12 weeks. Central arterial stiffness, hemodynamics and CVD risk factors were assessed at baseline and post-intervention. Analysis of covariance (ANCOVA) was used to examine changes following HIIT, MICT and PLA. RESULTS: Thirty-five participants (age: 55.1 ± 1.4 years, BMI: 36.1 ± 0.8 kg/m2) completed the study. A significant intervention effect was found for changes in pulse wave velocity (PWV) (p = .03), which reduced with HIIT (-0.3 ± 0.9 m/s) and MICT (-0.1 ± 1.1 m/s) but increased with PLA (0.8 ± 1.6 m/s). There was a significant intervention effect for changes in V̇O2peak (p < .01), glycosylated hemoglobin (p = .03), systolic blood pressure (p < .01), and waist circumference (p = .03), which all improved following MICT or HIIT but not PLA; there was no difference between MICT and HIIT. CONCLUSIONS: Twelve minutes of low-volume HIIT per week leads to improvements in central arterial stiffness and cardiovascular health in inactive individuals with obesity and T2D.

Exercise alone and exercise combined with education both prevent episodes of low back pain and related absenteeism: systematic review and network meta-analysis of randomised controlled trials (RCTs) aimed at preventing back pain.

OBJECTIVES: We aimed to investigate which prevention strategies for low back pain (LBP) are most effective. DESIGN: We completed a Bayesian network meta-analysis to summarise the comparative effectiveness of LBP prevention strategies. The primary outcomes were an episode of LBP and LBP-associated work absenteeism represented as ORs with associated 95% credibility intervals (CrIs). We ranked all prevention strategies with surface under the cumulative ranking curve (SUCRA) analysis. DATA SOURCES: PubMed, EMBASE and CENTRAL databases were searched along with manual searches of retrieved articles. We only included randomised controlled trials (RCTs) that reported an episode of LBP and/or LBP-associated work absenteeism evaluating LBP prevention strategies were included. ELIGIBILITY CRITERIA FOR SELECTING STUDIES: Data were independently extracted by two investigators, and RCT quality was assessed using the Cochrane Risk of Bias tool. RESULTS AND SUMMARY: Forty RCTs were included. Exercise combined with education (OR: 0.59, CrI: 0.41 to 0.82) and exercise alone (OR: 0.59, CrI: 0.36 to 0.92) both prevented LBP episodes; exercise combined with education and education alone both had large areas under the curve (SUCRA: 81.3 and 79.4, respectively). Additionally, exercise (OR: 0.04, CrI: 0.00 to 0.34) prevented LBP-associated work absenteeism, with exercise and the combination of exercise and education ranking highest (SUCRA: 99.0 and 60.2, respectively). CONCLUSIONS: Exercise alone and exercise combined with education can prevent episodes of LBP and LBP-related absenteeism. TRIAL REGISTRATION NUMBER: PROSPERO 42017056884.

Calf muscle stretching is ineffective in increasing ankle range of motion or reducing plantar pressures in people with diabetes and ankle equinus: A randomised controlled trial.

BACKGROUND: Limited ankle dorsiflexion, or equinus, is associated with elevated plantar pressures, which have been implicated in the development and non-healing of foot ulcer. A stretching intervention may increase ankle dorsiflexion and reduce plantar pressures in people with diabetes. METHODS: Two arm parallel randomised controlled trial from September 2016 to October 2017. Adults with diabetes and ankle equinus (≤5° dorsiflexion) were randomly allocated to receive an 8 week static calf stretching intervention or continue with their normal activities. Primary outcome measures were change in weight bearing and non-weight bearing ankle dorsiflexion and forefoot peak plantar pressure. Secondary outcome measures were forefoot pressure time integrals and adherence to the stretching intervention. FINDINGS: 68 adults (mean (standard deviation) age and diabetes duration 67.4 (10.9) years and 14.0 (10.8) years, 64.7% male) were randomised to stretch (n = 34) or usual activity (n = 34). At follow up, no significant differences were seen between groups (adjusted mean difference) for non-weight (+1.3°, 95% CI:-0.3 to 2.9, p = 0.101) and weight bearing ankle dorsiflexion (+0.5°, 95% CI:-2.6 to 3.6, p = 0.743) or forefoot in-shoe (+1.5 kPa, 95% CI:-10.0 to 12.9, p = 0.803) or barefoot peak pressures (-19.1 kPa, 95% CI:-96.4 to 58.1, p = 0.628). Seven of the intervention group and two of the control group were lost to follow up. INTERPRETATION: Our data failed to show a statistically significant or clinically meaningful effect of static calf muscle stretching on ankle range of motion, or plantar pressures, in people with diabetes and ankle equinus.

Self-reported physical activity in community-dwelling adults with diabetes and its association with diabetes complications.

AIMS: To describe the physical activity levels of an Australian community-based adult population with diabetes, and investigate the interaction between diabetes complications and physical activity. METHODS: Anthropometric, demographic, biochemical and self-reported physical activity measures (IPAQ) were performed. Associations and multiple regression analyses were undertaken between physical activity, known risk factors for diabetes complications, and history of cardiovascular disease (CVD), neuropathy and foot ulceration obtained from medical records. RESULTS: 240 participants were recruited (96% type 2 diabetes; age 68.7 ±â€¯10.5 y; 58% men; diabetes duration 14.3 ±â€¯11.4 y). Sixty seven percent of participants reported undertaking moderate or vigorous intensity exercise to recommended levels, and 29% reported no moderate-vigorous exercise. In addition to being associated with known demographic and biochemical risk factors and other complications, diabetes complications were also associated with different physical activity behaviours. Individuals with a history of CVD were more likely to participate in moderate-vigorous exercise and meet exercise guidelines, individuals with neuropathy undertook less walking and moderate intensity exercise, and those with a history of foot ulceration sat more and participated less in vigorous exercise. CONCLUSIONS: In Australian adults, the presence of diabetes complications may influence physical activity participation, and associate with characteristic physical activity approaches.

Restriction in lateral bending range of motion, lumbar lordosis, and hamstring flexibility predicts the development of low back pain: a systematic review of prospective cohort studies.

BACKGROUND: Low back pain (LBP) is an increasingly common condition worldwide with significant costs associated with its management. Identification of musculoskeletal risk factors that can be treated clinically before the development of LBP could reduce costs and improve the quality of life of individuals. Therefore the aim was to systematically review prospective cohort studies investigating lower back and / or lower limb musculoskeletal risk factors in the development of LBP. METHODS: MEDLINE, EMBASE, AMED, CINAHL, SPORTDiscus, and the Cochrane Library were searched from inception to February 2016. No age, gender or occupational restrictions of participants were applied. Articles had to be published in English and have a 12 month follow-up period. Musculoskeletal risk factors were defined as any osseous, ligamentous, or muscular structure that was quantifiably measured at baseline. Studies were excluded if participants were pregnant, diagnosed with cancer, or had previous low back surgery. Two authors independently reviewed and selected relevant articles. Methodological quality was evaluated independently by two reviewers using a generic tool for observational studies. RESULTS: Twelve articles which evaluated musculoskeletal risk factors for the development of low back pain in 5459 participants were included. Individual meta-analyses were conducted based on risk factors common between studies. Meta-analysis revealed that reduced lateral flexion range of motion (OR = 0.41, 95% CI 0.24-0.73, p = 0.002), limited lumbar lordosis (OR = 0.73, 95% CI 0.55-0.98, p = 0.034), and restricted hamstring range of motion (OR = 0.96, 95% CI 0.94-0.98, p = 0.001) were significantly associated with the development of low back pain. Meta-analyses on lumbar extension range of motion, quadriceps flexibility, fingertip to floor distance, lumbar flexion range of motion, back muscle strength, back muscle endurance, abdominal strength, erector spinae cross sectional area, and quadratus lumborum cross sectional area showed non-significant results. CONCLUSION: In summary, we found that a restriction in lateral flexion and hamstring range of motion as well as limited lumbar lordosis were associated with an increased risk of developing LBP. Future research should aim to measure additional lower limb musculoskeletal risk factors, have follow up periods of 6-12 months, adopt a standardised definition of LBP, and only include participants who have no history of LBP.

Post-occlusive reactive hyperaemia of skin microvasculature and foot complications in type 2 diabetes.

AIMS: Diabetes-related microvascular disease has been implicated in the development of foot ulceration and amputation. Assessment of microvascular function may be effective in identifying those at risk of diabetic foot complications. We investigated the relationship between active or previous foot complication and post-occlusive reactive hyperaemia (PORH) measured by laser-Doppler fluxmetry (LDF) in people with type 2 diabetes. METHODS: PORH measures were obtained from the hallux apex in 105 people with type 2 diabetes. Associations were investigated between active or previous foot complication and PORH measures: time to peak (TtPeak) and peak as a percentage of baseline (P%BL). Multinomial logistic regression was used to determine the association of PORH with the likelihood of active foot ulcer or previous foot complication. RESULTS: For each second increase in TtPeak, the likelihood of a participant having a history of foot complication is increased by 2% (OR=1.019, p=0.01). This association was not reflected in people with an active foot ulcer (OR=1.003, p=0.832). P%BL was not found to be significantly different between those with a current or previous foot complication and those without (p=0.404). CONCLUSIONS: This investigation in a cohort with type 2 diabetes has demonstrated that longer TtPeak is associated with history of diabetic foot complications.

Effect of resistance training on liver fat and visceral adiposity in adults with obesity: A randomized controlled trial.

AIM: Regular aerobic exercise reduces visceral adipose tissue (VAT) and liver fat, however, not all individuals are able to adopt and adhere to such programs. Progressive resistance training (PRT) may be an alternative therapy, but there is limited available evidence. We examined the efficacy of PRT as per current exercise guidelines, compared with sham exercise placebo on liver fat and VAT. METHODS: Twenty-nine inactive and overweight/obese (body mass index ≥25 kg/m2 ) adults (age 29-59) were randomized to receive 8 weeks of PRT (n = 15, 10 exercises per session, 8-12 repetitions, 2-3 sets per exercise at 80-85% of one-repetition maximum, 3 days per week) or a sham exercise placebo control (CON) (n = 14). Change in liver fat, VAT, and abdominal s.c. adipose tissue (SAT) were assessed by magnetic resonance spectroscopy and imaging). RESULTS: There were no significant group by time interactions for change in liver fat in PRT versus CON groups (-0.07 ± 0.31% vs. 0.55 ± 0.77%, respectively, P = 0.19), VAT (-175 ± 85 cm3 vs. 10 ± 64 cm3 , respectively, P = 0.11), or abdominal SAT (-436 ± 245 cm3 vs. 127.29 ± 182 cm3 , respectively, P = 0.10) despite a significant increase in muscle volume (55 ± 78 cm3 vs. -0.04 ± 8 cm3 , respectively, P = 0.03). CONCLUSION: Traditional PRT is not effective for reducing liver fat in overweight/obese adults compared with placebo control. Although PRT has known metabolic benefits, an adequate volume of aerobic exercise should be promoted if liver fat is the therapeutic target.

The effect of exercise training on cutaneous microvascular reactivity: A systematic review and meta-analysis.

OBJECTIVES: This study aimed to review the efficacy of exercise training for improving cutaneous microvascular reactivity in response to local stimulus in human adults. DESIGN: Systematic review with meta-analysis. METHODS: A systematic search of Medline, Cinahl, AMED, Web of Science, Scopus, and Embase was conducted up to June 2015. Included studies were controlled trials assessing the effect of an exercise training intervention on cutaneous microvascular reactivity as instigated by local stimulus such as local heating, iontophoresis and post-occlusive reactive hyperaemia. Studies where the control was only measured at baseline or which included participants with vasospastic disorders were excluded. Two authors independently reviewed and selected relevant controlled trials and extracted data. Quality was assessed using the Downs and Black checklist. RESULTS: Seven trials were included, with six showing a benefit of exercise training but only two reaching statistical significance with effect size ranging from -0.14 to 1.03. The meta-analysis revealed that aerobic exercise had a moderate statistically significant effect on improving cutaneous microvascular reactivity (effect size (ES)=0.43, 95% CI: 0.08-0.78, p=0.015). CONCLUSIONS: Individual studies employing an exercise training intervention have tended to have small sample sizes and hence lacked sufficient power to detect clinically meaningful benefits to cutaneous microvascular reactivity. Pooled analysis revealed a clear benefit of exercise training on improving cutaneous microvascular reactivity in older and previously inactive adult cohorts. Exercise training may provide a cost-effective option for improving cutaneous microvascular reactivity in adults and may be of benefit to those with cardiovascular disease and metabolic disorders such as diabetes.

Cross-sectional correlations between the toe brachial index and lower limb complications in older people.

The aim of the study was to investigate the relationship between the toe brachial index (TBI) and foot ulceration and amputation in older people. Two hundred and sixty-one participants meeting guidelines for lower limb vascular assessment had their toe and brachial blood pressure measured, medical records audited and signs and symptoms of peripheral arterial disease (PAD) recorded. Pearson's correlation and linear regression analyses were performed to determine the strength of relationships between variables. Significant correlations were found between the TBI and painful symptoms (r = -0·35, P < 0·05) and foot complications (r = -0·31, P < 0·05). After adjusting for traditional risk factors for foot complications, participants with a TBI <0·70 were 19 times more likely to have a history of foot wounds or amputation (odds ratio = 19·20, 95% confidence interval (CI): 2·36-155·96, P < 0·001) than those with higher TBI values (>0·70). This preliminary study supports a TBI threshold of 0·70 for PAD diagnosis and indicates that lower values are associated with painful symptoms, history of ulceration and amputation. Future longitudinal investigation of the predictive capacity is now warranted.

Peripheral sensory neuropathy is associated with altered postocclusive reactive hyperemia in the diabetic foot.

OBJECTIVE: This study examined whether the presence of peripheral sensory neuropathy or cardiac autonomic deficits is associated with postocclusive reactive hyperemia (reflective of microvascular function) in the diabetic foot. RESEARCH DESIGN AND METHODS: 99 participants with type 2 diabetes were recruited into this cross-sectional study. The presence of peripheral sensory neuropathy was determined with standard clinical tests and cardiac autonomic function was assessed with heart rate variation testing. Postocclusive reactive hyperemia was measured with laser Doppler in the hallux. Multiple hierarchical regression was performed to examine relationships between neuropathy and the peak perfusion following occlusion and the time to reach this peak. RESULTS: Peripheral sensory neuropathy predicted 22% of the variance in time to peak following occlusion (p<0.05), being associated with a slower time to peak but was not associated with the magnitude of the peak. Heart rate variation was not associated with the postocclusive reactive hyperemia response. CONCLUSIONS: This study found an association between the presence of peripheral sensory neuropathy in people with diabetes and altered microvascular reactivity in the lower limb.

Foot bone density in diabetes may be unaffected by the presence of neuropathy.

AIMS: Neuropathies are common complications of diabetes and are proposed to influence peripheral bone, principally via an altered vascular supply. This study aimed to determine the relationship between subtypes of neuropathy and vascular reactivity on foot bone density in people with diabetes. METHODS: A case-control observational design was utilised with two groups: those with diabetic peripheral large fibre neuropathy (n=23) and a control group with diabetes but without neuropathy (n=23). Bone density in 12 foot bones was determined with computed tomography scanning. Additionally, post-occlusive reactive hyperemia, presence of small fibre neuropathy and heart rate variability were determined. T-tests and hierarchical regression were used to examine the relationships among the variables. RESULTS: No difference in foot bone density was found between those with and those without large fibre neuropathy. Furthermore, no association between heart rate variability or reactive hyperemia and bone density was found. Small fibre neuropathy was associated with increased cuboid trabecular bone density (p=0.006) with its presence predictive of 14% of the variance. CONCLUSIONS: This study found no clear association between presence of diabetic neuropathies and foot bone density. Furthermore, vascular reactivity appears to have no impact on bone density.

The effect of pretest rest time on automated measures of toe systolic blood pressure and the toe brachial index.

OBJECTIVES: Evaluation of peripheral blood supply is fundamental to risk categorization and subsequent ongoing monitoring of patients with lower extremity peripheral arterial disease. Toe systolic blood pressure (TSBP) and the toe brachial index (TBI) are both valid and reliable vascular screening techniques that are commonly used in clinical practice. However, the effect of pretest rest duration on the magnitude of these measurements is unclear. METHODS: Eighty individuals meeting current guidelines for lower extremity peripheral arterial disease screening volunteered to participate. The Systoe and MicroLife automated devices were used to measure toe and brachial systolic blood pressures, respectively, following 5, 10 and 15 min of rest in a horizontal supine position. A ratio of TSBP to brachial pressure was used to calculate the TBI and change in TBI at each time interval was investigated. RESULTS: A significant increase in TSBP [3.66 mmHg; 95% confidence interval (CI): 1.44-5.89; P≤0.001] and the TBI (0.03; 95% CI: 0.01-0.05; P≤0.001) occurred between 5 and 10 min. Between 10 and 15 min, there was a nonsignificant decrease in TSBP (-0.73 mmHg; 95% CI: -1.48 to 2.93; P=1.000) and the TBI (0.00; 95% CI: -0.02 to 0.02; P=1.000). CONCLUSION: Ten minutes of pretest rest is recommended for measurement of TSBP and for both pressure measurements used in the calculation of a TBI to ensure that stable pressures are measured.

Effect of aerobic exercise training dose on liver fat and visceral adiposity.

BACKGROUND & AIMS: Aerobic exercise reduces liver fat and visceral adipose tissue (VAT). However, there is limited data from randomized trials to inform exercise programming recommendations. This study examined the efficacy of commonly prescribed exercise doses for reducing liver fat and VAT using a randomized placebo-controlled design. METHODS: Inactive and overweight/obese adults received 8 weeks of either; i) low to moderate intensity, high volume aerobic exercise (LO:HI, 50% VO 2peak, 60 min, 4d/week); ii) high intensity, low volume aerobic exercise (HI:LO, 70% VO 2peak, 45 min, 3d/week); iii) low to moderate intensity, low volume aerobic exercise (LO:LO, 50% VO 2peak, 45 min, 3d/week); or iv) placebo (PLA). Liver fat (spectroscopy) and VAT (magnetic resonance imaging) were measured before and after intervention. RESULTS: Forty-seven of the 48 (n = 12 in each group) participants completed the trial. There were no serious adverse events. There was a significant change in group × time interaction in liver fat, which reduced in HI:LO by 2.38 ± 0.73%, in LO:HI by 2.62 ± 1.00%, and in LO:LO by 0.84 ± 0.47% but not in PLA (increase of 1.10 ± 0.62%) (p = 0.04). There was a significant reduction in VAT in HI:LO (-258.38 ± 87.78 cm(3)), in LO:HI (-386.80 ± 119.5 cm(3)), and in LO:LO (-212.96 ± 105.54 cm(3)), but not in PLA (92.64 ± 83.46 cm(3)) (p = 0.03). There were no significant differences between the dose or intensity of the exercise regimen and reductions in liver fat or VAT (p > 0.05). CONCLUSION: The study found no difference in efficacy of liver fat reduction by either aerobic exercise dose or intensity. All of the aerobic exercise regimens employed reduced liver fat and VAT by a small amount without clinically significant weight loss.

Effect of premeasurement rest time on systolic ankle pressure.

BACKGROUND: Systolic ankle pressures are routinely measured as part of an ankle-brachial index to screen for lower extremity peripheral arterial disease. Despite widespread use of this measurement, the effect of premeasurement duration of rest on the magnitude, or reliability of the ankle systolic pressure measurement is unknown. This study assessed the effect of premeasurement rest duration on systolic ankle pressures. METHODS AND RESULTS: One hundred and forty participants meeting guidelines for peripheral arterial disease screening volunteered for this study. Following 5 minutes of rest in the supine horizontal position, ankle systolic pressures of the lower extremity were taken. Measurements were repeated at 10 and 15 minutes. Testing was repeated 7 to 10 days later. A significant drop in ankle pressure of 5.02 mm Hg occurred between 5 and 10 minutes (P=0.004). No significant change occurred between 10 and 15 minutes (mean change 0.15 mm Hg, P=0.99). Presence of diabetes was associated with a smaller drop between 5 and 15 minutes (mean change 1.85 mm Hg) and predicted 13.4% of the variance in change in ankle pressure (ß=-3.61, P=0.0001). Test-retest reliability after 5 minutes was excellent (intraclass correlation coefficient: 0.84, 95% CI: 0.76 to 0.91) however increased for measurements taken at 10 and 15 minutes (intraclass correlation coefficient: 0.89 95% CI: 0.83 to 0.94 and 0.89 95% CI: 0.82 to 0.93). CONCLUSIONS: Results suggest ankle systolic pressures stabilise after 10 minutes of rest. Longer periods of premeasurement rest did not improve reliability significantly. Though diabetes affects ankle pressure changes after rest, further investigation is required to identify the cause.

Exercise performance over the menstrual cycle in temperate and hot, humid conditions.

PURPOSE: This study investigated the effects of the menstrual cycle on prolonged exercise performance both in temperate (20°C, 45% relative humidity) and hot, humid (32°C, 60% relative humidity) conditions. METHODS: For each environmental condition, 12 recreationally active females were tested during the early follicular (day 3-6) and midluteal (day 19-25) phases, verified by measurement of estradiol and progesterone. For all four tests, thermoregulatory, cardiorespiratory, and perceptual responses were measured during 60 min of exercise at 60% of maximal oxygen consumption followed by an incremental test to exhaustion. RESULTS: No differences in exercise performance between menstrual cycle phases were found during temperate conditions (n = 8) despite a higher resting and submaximal exercise core temperature (Tc) in the luteal phase. In hot, humid conditions (n = 8), however, prolonged exercise performance, as exercise time to fatigue, was significantly reduced during the luteal phase. This finding was not only accompanied by higher resting and submaximal exercise Tc but also a higher rate of increase in Tc during the luteal phase. Furthermore, submaximal exercise HR, minute ventilation, and RPE measures were higher during the luteal phase in hot, humid conditions. No significant differences were found over the menstrual cycle in heat loss responses (partitional calorimetry, sweat rate, upper arm sweat composition) and Tc at exhaustion. CONCLUSION: In temperate conditions, no changes in prolonged exercise performance were found over the menstrual cycle, whereas in hot, humid conditions, performance was decreased during the luteal phase. The combination of both exercise and heat stress with the elevated luteal phase Tc at the onset of exercise resulted in physiological and perceptual changes and a greater thermosensitivity, which may explain the decrease in performance.

Proximal and distal contributions to lower extremity injury: a review of the literature.

Excessive or prolonged foot pronation has been linked to the development of numerous overuse injuries affecting the lower limb. The originally proposed pathomechanical model suggests foot motion affects more proximal structures through disruption of distal to proximal coupling between the foot, tibia, femur, and hip. Research evidence supports the presence of a dynamic coupling mechanism between lower limb segments, however, the direction of the coupling is inconclusive. Recent prospective investigations of the role of the lumbo-pelvic hip complex have identified a strong association between proximal dysfunction and increased risk of lower limb injuries. Strength of muscles of the lumbo-pelvic hip complex (core muscles) is suggested to be essential to controlling hip abduction, subsequent internal rotation of the femur and potentially more distal movement. Proximal muscle weakness and altered motor control have also been implicated in the development of numerous lower limb injuries, many of which have previously been attributed to excessive foot pronation. This review discusses the theoretical basis for the role of proximal and distal structures in biomechanical dysfunction of the lower limb and the development of lower limb overuse injury. Current prospective evidence relating to the contributions of excessive foot pronation and core muscle function to the development of lower extremity injury is evaluated.