Effects of high-intensity progressive resistance training on self-reported health status in older persons with type 2 diabetes

Purpose: To evaluate the influence of high-intensity progressive resistance training (PRT) on self-reported physical and mental health in older persons with type 2 diabetes.

Methods: We performed a 12-month RCT with 36 overweight men and women with type 2 diabetes (aged 60-80 years) who were randomly assigned to a moderate weight-loss diet plus PRT (PRT&WL) or a moderate weight-loss diet plus a control (stretching) program (WL). Gymnasium-based training for 6 months was followed by an additional 6 months of home-based training. The SF-36 (v1) questionnaire was used to obtain physical (PCS) and mental (MCS) health component summary scores at baseline, 6 and 12 months.

Results: Subject retention was 81% and 72% after 6 and 12 months respectively. Exercise adherence during gymnasium- and home-based training was 88% and 73% for the PRT&WL group, and 85% and 78.1% for the WL group respectively. In a regression model adjusted for age and sex, PCS improved in the PRT&WL group compared to the WL group after 6 months of gymnasium-based training (2.3 versus -2.0, p = 0.05), which persisted after 12 months training (0.7 versus -4.1, p = 0.03). There were no between-group differences at 6 or 12 months for the MCS.

Conclusion: High-intensity PRT was effective in improving self-reported physical health, but not mental health. PRT provides an effective exercise alternative in lifestyle management for older adults with type 2 diabetes.

The need to accumlate human capital across levels of export intensity : activating resources that are increasingly difficult to mobilise

With increasing levels of export intensity, firms begin to face new demands. The first set of resources brought to bear on the issues, and those resources that are most quickly mobilised, are the employees. Indeed, higher levels of exporting require activating relatively less mobile resources through the building of organisational structures and mechanisms for managing repositories of knowledge (particularly organisational specialisation and selectively hiring appropriately skilled staff). This paper explores the management of human capital across different levels of export activity in Australian manufacturing firms. Analyses were based on 90 Australian-headquartered manufacturing exporters that responded to a survey. Overall, the results support the notion that firms need to accumulate knowledge as they internationalise. These results are discussed in terms of their consequences for HRM practices.

Negative beliefs about low back pain are associated with high pain intensity and high level disability in community-based women

Background Although previous studies have investigated beliefs about back pain in clinical and employed populations, there is a paucity of data examining the beliefs of the broader community. We aimed to characterize the beliefs that community-dwelling women have about back pain and its consequences, and to determine whether those with varying levels of pain intensity and disability differ in their beliefs. Methods 542 community-dwelling women, aged 24 to 80 years, were recruited from a research database. Participants completed a self-administered questionnaire that included detailed demographic information, the Chronic Pain Grade Questionnaire (CPG) and the Back Beliefs Questionnaire (BBQ). The CPG examined individuals' levels of pain intensity and disability, and the BBQ investigated their beliefs about back pain and its consequences. Results 506 (93.4%) women returned the study questionnaire. The mean (SD) BBQ score for the cohort was 30.7 (6.0), indicating generally positive beliefs about back pain. However, those women with high intensity pain and high level disability had a mean (SD) score of 28.5 (5.7) and 24.8 (5.7) respectively, which reflects greater negativity about back pain and its consequences. There was an association between negative beliefs and high pain intensity (OR = 0.94 (95% CI: 0.90, 0.99), p = 0.01) and high level disability (OR = 0.93 (95% CI: 0.89, 0.97), p = 0.001), after adjusting for confounders. Conclusion This study highlights that although women living in the community were generally positive about back pain, subgroups of women with high pain intensity and high level disability were identified who had more pessimistic views. While a causal relationship cannot be inferred from these cross-sectional data, the results suggest that negative beliefs individuals have about back pain may be predictive of chronic, disabling spinal pain.

Low-intensity pulsed ultrasound for chronic patellar tendinopathy : a randomized, double-blind, placebo-controlled trial

Objective. Patellar tendinopathy (PT) is a common and significant clinical condition for which there are few established interventions. One intervention that is currently being used clinically to manage PT symptoms is the introduction of low-intensity pulsed ultrasound (LIPUS). The aim of this study was to investigate the clinical efficacy of LIPUS in the management of PT symptoms.

Methods. A randomized, double-blind, placebo-controlled study was conducted. Volunteers with clinically and radiologically confirmed PT were randomly allocated to either an active-LIPUS (treatment) or inactive-LIPUS (placebo) group. LIPUS was self-administered by participants for 20 min/day, 7 days/week for 12 weeks. All participants also completed a daily, standardized eccentric exercise programme based on best practice. Primary outcomes were change in pain during the participant's most aggravating activity in the preceding week, measured on 10 cm visual analogue scales for both usual (VAS-U) and worst (VAS-W) tendon pain.

Results. Out of 156 individuals who volunteered, 37 met the eligibility criteria and were randomized to either active-LIPUS (n = 17) or inactive-LIPUS (n = 20). Using an intention-to-treat analysis, VAS-U and VAS-W for the entire cohort decreased by 1.6 ± 1.9 cm (P < 0.01) and 2.5 ± 2.4 cm (P < 0.01), respectively. There were no differences between the active- and inactive-LIPUS groups for change in VAS-U (–0.2 cm; 95% CI, –1.5, 1.1 cm) (P = 0.74) or VAS-W (–0.5 cm; 95% CI, –2.1, 1.1 cm) (P = 0.57). A per-protocol analysis provided similar results.

Conclusions. These findings suggest that LIPUS does not provide any additional benefit over and above placebo in the management of symptoms associated with PT.

Effect of exercise intensity and hypoxia on skeletal muscle AMPK signaling and substrate metabolism in humans

We compared in human skeletal muscle the effect of absolute vs. relative exercise intensity on AMP-activated protein kinase (AMPK) signaling and substrate metabolism under normoxic and hypoxic conditions. Eight untrained males cycled for 30 min under hypoxic conditions (11.5% O2, 111 ± 12 W, 72 ± 3% hypoxia VO2 peak; 72% Hypoxia) or under normoxic conditions (20.9% O2) matched to the same absolute (111 ± 12 W, 51 ± 1% normoxia VO2 peak; 51% Normoxia) or relative (to VO2 peak) intensity (171 ± 18 W, 73 ± 1% normoxia VO2 peak; 73% Normoxia). Increases (P < 0.05) in AMPK activity, AMPK{alpha} Thr172 phosphorylation, ACCbeta Ser221 phosphorylation, free AMP content, and glucose clearance were more influenced by the absolute than by the relative exercise intensity, being greatest in 73% Normoxia with no difference between 51% Normoxia and 72% Hypoxia. In contrast to this, increases in muscle glycogen use, muscle lactate content, and plasma catecholamine concentration were more influenced by the relative than by the absolute exercise intensity, being similar in 72% Hypoxia and 73% Normoxia, with both trials higher than in 51% Normoxia. In conclusion, increases in muscle AMPK signaling, free AMP content, and glucose disposal during exercise are largely determined by the absolute exercise intensity, whereas increases in plasma catecholamine levels, muscle glycogen use, and muscle lactate levels are more closely associated with the relative exercise intensity.

Procedural justice and affect intensity : understanding reactions to regulatory authorities

Why is it that some people respond in a more negative way to procedural injustice than do others, and why is it that some people go on to defy authority while others in the same situation do not? Personality theorists suggest that the psychological effect of a situation depends on how a person interprets the situation and that such differences in interpretation can vary as a function of individual difference factors. For example, affect intensity—one’s predisposition to react more or less emotionally to an event—is one such individual difference factor that has been shown to influence people’s reactions to events. Cross-sectional survey data collected from (a) 652 tax offenders who have been through a serious law enforcement experience (Study 1), and (b) 672 citizens with recent personal contact with a police officer (Study 2), showed that individual differences in ‘affect intensity’ moderate the effect of procedural justice on both affective reactions and compliance behavior. Specifically, perceptions of procedural justice had a greater effect in reducing anger and reports of non-compliance among those lower in affect intensity than those higher in affect intensity. Both methodological and theoretical explanations are offered to explain the results, including the suggestion that emotions of shame may play a role in the observed interaction.

Effect of posture on high-intensity constant-load cycling performance in men and women

The time sustained during a graded cycle exercise is ~10% longer in an upright compared with a supine posture. However, during constant-load cycling this effect is unknown. Therefore, we tested the postural effect on the performance of high-intensity constant-load cycling. Twenty-two active subjects (11 men, 11 women) performed two graded tests (one upright, one supine), and of those 22, 10 subjects (5 men, 5 women) performed three high-intensity constant-load tests (one upright, two supine). To test the postural effect on performance at the same absolute intensity, during the upright and one of the supine constant-load tests subjects cycled at 80% of the peak power output achieved during the upright graded test. To test the postural effect on performance at the same relative intensities, during the second supine test subjects cycled at 80% of the peak power output achieved during the supine graded test. Exercise time on the graded and absolute intensity constant-load tests for all subjects was greater (P<0.05) in the upright compared with supine posture (17.9±3.5 vs. 16.1±3.1 min for graded; 13.2±8.7 vs. 5.2±1.9 min for constant-load). This postural effect at the same absolute intensity was larger in men (19.4±8.5 upright vs. 6.6±1.6 supine, P<0.001) than women (7.1±2 upright vs. 3.9±1.4 supine, P>0.05) and it was correlated (P<0.05) with both the difference in VO₂ between positions during the first minute of exercise (r=0.67) and the height of the subjects (r=0.72). In conclusion, there is a very large postural effect on performance during constant-load cycling exercise and this effect is significantly larger in men than women.

Effects of strength, flexibility and moderate intensity cardiovascular exercise on measures of fitness in sedentary women

The maintenance of functional physical fitness across the lifespan depends upon the presence or absence of disease, injury, and the level of habitual physical activity. The prevalence of sedentariness rises with increasing age culminating in 31% of elderly women being classified as leading a sedentary lifestyle. Exercise prescription that involves easily accomplished physical activity may result in the maintenance of mobility into old age through a reduction in the risk of premature death and disablement from cardiovascular disease and a reduction in the risk of falls and injuries from falls. It may be that short bouts of physical activity are more appealing to the sedentary and to those in full time employment than longer bouts, and it may be that short bouts of exercise, performed three times per day, can improve physical fitness. The purpose of this study was therefore to examine the problem: Does exercise session duration, initial cardiovascular fitness, and age group effect changes in functional physical fitness in sedentary women training for strength, flexibility and aerobic fitness? Twenty-three, sedentary women aged between 19 and 54 years who were employed at a major metropolitan hospital undertook six weeks of moderate intensity physical activity in one of two training groups. Participants were randomly allocated to either short duration (3 x 10 minute), or long duration (30 minute), exercise groups. The 3 x 10 minute group (n=13), participated in three, 10 minute sessions per day separated by at least 2 hours, 3 days per week. The 30 minute group (n=10), participated in three 30 minute sessions per week. The total amount of work was similar, with an average of 129 and 148 kcal training day for the 3 x 10 minute and 30 minute groups, respectively. The training program incorporated three walking and stair climbing courses for aerobic conditioning, a series of eleven static stretches for joint flexibility, and isotonic and isometric strength exercises for lower and upper body muscular strength. Measures of functional strength, functional flexibility and cardiovascular fitness were assessed prior to training, and immediately following the six week exercise program. A two way analysis of variance (Group x Time) was used to examine the effect of training and group on the dependent variables. The level of significance, 0.05 was adopted for all statistical tests. Mean hand grip strength showed for both groups no significant change over time for the 3 x 10 minute group (30.7kg to 31.7kg) and 30 minute group (30.2kg to 32.4kg). Leg strength showed a trend for improvement (p=0.098) in both the 3 x 10 minute and 30 minute training groups representing a 15% and 18% improvement, respectively. Combined right and left neck rotation significantly improved in the 3 x 10 minute group (82.8° to 92.0°) and 30 minute group (82.5° to 91.5°). Wrist flexion and extension improved significantly in 3 out of the 4 measurements. Left wrist flexion improved significantly by an average of 7.0% for the 3 x 10 minute and 4.9% for the 30 minute group. Right and left wrist extension improved significantly in the 3 x 10 minute and 30 minute training groups (5.9% and 6.8%, respectively). Hip and spine flexibility improved 3.4cm (35.2cm to 38.6cm) in the 3 x 10 minute group, and 6.6cm (37.4cm to 44.0cm) in the 30 minute group. There was a significant improvement in cardiovascular fitness for both groups representing a 22% improvement in the 3 x 10 minute group (27.2 to 33.2 ml kg min), and a 25% improvement in the 30 minute group (27.5 to 34.4 ml -kg min). No significant difference was shown in the degree of improvement in cardiovascular fitness over six weeks of training for subjects of either low or moderate initial aerobic fitness. Grip strength showed no significant changes over time for either the young-aged (19-35 years) or middle-aged (36-54 years) groups. Leg strength showed a trend for improvement (p=0.093) in the young-aged group (63.5kg to 71.9kg) and middle-aged group (69.3kg to 85.8kg). Neck rotation flexibility improved a similar amount in both the young and middle aged groups representing an improvement of 9.9° and 8.0° respectively. There was significant improvement in two of the four measures of wrist flexibility. Hip and spine flexibility was significantly greater in the young-aged group compared to the middle-aged group (38.5cm and 30.7cm, respectively). There was a significant improvement in hip and spine flexibility over the six week training program representing an increase in reach of 6.5cm for the young age group and 4.9cm for the older group. The middle-aged subjects had significantly lower cardiovascular fitness than their younger peers, scoring 22.8 and 30.7 ml -kg min, respectively. Cardiovascular fitness improved a similar amount in both age groups representing a significant improvement of 23.8% and 28.1% for the younger-aged and middle-aged subjects, respectively. The findings of this study suggest that short bouts of exercise may be equally as effective as longer bouts of exercise for improving the flexibility and cardiovascular components of functional physical fitness in sedentary young and middle aged women. Additionally short bouts of exercise may be more attractive than longer bouts of exercise for the beginning exerciser as they may more easily fit into the busy lifestyle encountered by many people in today's society. Sedentary young and middle-aged women should benefit from static flexibility exercises designed to improve and/or maintain functional flexibility and thus maintain mobility and reduce the incidence of muscular injury. Regular, brisk walking, incorporating some stair climbing, is likely to be beneficial in improving cardiovascular health and perhaps also in improving leg strength, thereby helping to improve and maintain functional physical fitness for both young and middle-aged sedentary women.

Metabolic adaptations to short-term high-intensity interval training : a little pain for a lot of gain?

High-intensity interval training (HIT) is a potent time-efficient strategy to induce numerous metabolic adaptations usually associated with traditional endurance training. As little as six sessions of HIT over 2 wk or a total of only approximately 15 min of very intense exercise (~600 kJ), can increase skeletal muscle oxidative capacity and endurance performance and alter metabolic control during aerobic-based exercise.

Pacing strategy and high-intensity cycling performance

This thesis found that a brief maximal acceleration, followed by a steady effort thereafter is the most effective pacing strategy for intense, short-term cycling performance. This strategy leads to an increase in aerobic energy supply early in exercise, which contributes to a faster speed throughout the race.

The combined effect of light intensity and temperature on the chlorophyll and carotenoid pigments of phytoplankton

Chlorophyll a and other photosynthetic pigments are used as indicators of phytoplankton biomass, composition and physiological state. Extraction and HPLC procedures were developed to analyse for chlorophyll and carotenoid pigments. The effect of the environment on pigment production must be quantified before the pigments can be used to accurately estimate biomass or quantitatively describe phytoplankton composition.