Effects of low- and high-repetition resistive training on lipoprotein-lipid profiles

High plasma soluble levels of the immune checkpoint HLA-G molecule among bodybuilders

Introduction

Studies report that intense physical activity influences the down-regulation of immune function in athletes as well as the interaction between adipose tissue and the immune system.

Aim

This study aimed to compare the plasma soluble levels of the immune checkpoint HLA-G (sHLA-G) molecule with the fat mass and muscle mass index among 77 bodybuilders and 64 controls.

Results

The comparisons of the percentage of body fat (%BF) revealed that the groups of male and female bodybuilders showed a statistically significant reduction in the percentage of body fat when compared to their control group, (P <0.0001, for both comparisons). Regarding sHLA-G levels, the comparisons showed that the group of male bodybuilders had significantly higher sHLA-G levels compared to the group of female bodybuilders (P = 0.0011).

Conclusion

Our results showed that in bodybuilders with less body fat, the systemic levels of soluble HLA-G, an immunological molecule with recognized immunosuppressive function, are significantly higher and suggest that this immune mechanism may corroborate the immunosuppressive state in athletes undergoing intense and prolonged physical training.

The effects of daily food ingestion on improved immune functions and health promotion of bodybuilding athletes

The purpose of this study was to investigate the effects of different weight reduction methods on the body composition characteristics, cardiopulmonary functions, and health promotion of elite bodybuilding athletes in a comprehensive manner. For this purpose, the study analyzed the effects of two different weight reduction methods on 25 elite bodybuilding athletes registered at the Bodybuilding Association over a period of 6 weeks. There were interactive effects on macronutrients, macrominerals, and antioxidants according to weight reduction methods as the experiment group (6%±2%) maintained a certain amount of food intakes across various nutrients including energy intakes or made a slow decrease it, whereas the traditional group (16%±4%) made a sharp decrease in it due to relatively greater weight reduction than the experiment group and thus showed pattern differences from it. As for immunity variables, there was an increase to certain cytokines despite the traditional high weight reduction method, but it caused no excessive reduction of immunity or rapid decrease to certain factors of body composition. In addition, there were no significant differences in main and interactive effects on the one-repetition maximum of bench press and squat, which are two functional indicators of health promotion. These findings imply that the low weight reduction method within the range of 6%±2% minimized or maintained changes to muscle circumference or mass while causing no improvement to muscular strength.

Association between metabolic risk markers, body composition and different manifestations of strength in young adults

Introduction: For decades, low levels of muscle strength (MS) have been associated with an increased risk of mortality from all causes.Objective: To identify the correlation between values of different manifestations of MS and metabolic risk markers (MRM) in young university students.Materials and methods: The study included 50 participants (37 men, 13 women), aged between 19 and 23 years. The grip strength of both hands and the muscular strength of upper and lower limbs were evaluated, as well as height, weight, body mass index (BMI), skin folds, HDL, cholesterol and triglycerides.Results: No significant associations between MRM and the different manifestations of MS were found.Conclusion: MS and MRM are separately associated with mortality risk factors and with suffering from cardiovascular diseases

Relationships between different types of physical activity and metabolic syndrome among Taiwanese workers

This study aimed to investigate the relationships between different types of physical activity (PA) and metabolic syndrome (MetS). In this cross-sectional study, 3,296 Taiwanese workers were enrolled. A self-reported questionnaire was used to assess nutritional health behavior and PA levels related to occupation, leisure time, and commuting. Anthropometric measures, blood pressure and biochemical determinations of the blood were also obtained. Multiple logistic regression was used to evaluate the adjusted odds ratios (ORs) and 95% confidence intervals (CI) of MetS and its components associated with different types of PA. The prevalence of MetS was 16.6% in workers. Compared with a low level of leisure-time PA, a high level of leisure-time PA showed a significantly lower risk of high triglycerides (OR 0.73, 95% CI 0.61-0.87) and MetS (OR 0.76, 95% CI 0.62-0.95). Compared with a low level of occupational PA, a high level of occupational PA represented a significantly lower risk of both abdominal adiposity (OR 0.64, 95% CI 0.49-0.84) and high triglycerides (OR 0.71, 95% CI 0.55-0.90). However, commuting PA levels were not significantly associated with MetS and its components. In conclusion, occupational PA as well as leisure-time PA could be important for the prevention of MetS.

The effects of high-intensity resistance exercise on the blood lipid profile and liver function in hypercholesterolemic hamsters

It is well established that atherogenic dyslipidemia, characterized by high levels of triglycerides (TG), total cholesterol (TC), and low-density lipoprotein (LDL) cholesterol and low levels of high-density lipoprotein (HDL) cholesterol, constitutes important risk factors for cardiovascular disease. Regular exercise has been associated with a reduced risk for metabolic diseases. However, studies supporting the concept that resistance exercise is a modifier of blood lipid parameters are often contradictory. The aim of this study was to investigate the effects of high-intensity resistance exercise on the serum levels of TG, TC, HDL and non-HDL cholesterol, glucose, and the liver function enzymes alanine aminotransferase (ALT, EC 2.6.1.2) and aspartate aminotransferase (AST, EC 2.6.1.1) in golden Syrian hamsters (Mesocricetus auratus (Waterhouse, 1839)) fed a hypercholesterolemic diet. Sedentary groups (S) and exercise groups (E) were fed a standard diet (SS and ES) or a cholesterol-enriched diet (standard plus 1% cholesterol, SC and EC). Resistance exercise was performed by jumps in the water, carrying a load strapped to the chest, representing 10 maximum repetitions (10 RM, 30 s rest, five days per week for five weeks). Mean blood sample comparisons were made by ANOVA + Tukey or ANOVA + Kruskal-Wallis tests (p < 0.05) to compare parametric and nonparametric samples, respectively. There were no differences in blood lipids between the standard diet groups (SS and ES) (p > 0.05). However, the EC group increased the glucose, non-HDL, and TC levels in comparison with the ES group. Moreover, the EC group increased the TG levels versus the SC group (p < 0.05). In addition, the ALT levels were increased only by diet treatment. These findings indicated that high-intensity resistance exercise contributed to dyslipidemia in hamsters fed a hypercholesterolemic diet, whereas liver function enzymes did not differ in regards to the exercise protocol.

Low and moderate, rather than high intensity strength exercise induces benefit regarding plasma lipid profile

BACKGROUND

The effects of chronic aerobic exercise upon lipid profile has been previously demonstrated, but few studies showed this effect under resistance exercise conditions.

OBJECTIVE

The aim of this study was to examine the effects of different resistance exercise loads on blood lipids.

METHODS

Thirty healthy, untrained male volunteers were allocated randomly into four groups based at different percentages of one repetition maximum (1 RM); 50%-1 RM, 75%-1 RM, 90%-1 RM, and 110%-1 RM. The total volume (sets x reps x load) of the exercise was equalized. The lipid profile (Triglycerides [TG], HDL-cholesterol [HDL-c], LDL-cholesterol, and Total cholesterol) was determined at rest and after 1, 24, 48 and 72 h of resistance exercise.

RESULTS

The 75%-1 RM group demonstrated greater TG reduction when compared to other groups (p < 0.05). Additionally, the 110%-1 RM group presented an increased TG concentration when compared to 50% and 75% groups (p = 0.01, p = 0.01, respectively). HDL-c concentration was significantly greater after resistance exercise in 50%-1 RM and 75%-1 RM when compared to 110%-1 RM group (p = 0.004 and p = 0.03, respectively). Accordingly, the 50%-1 RM group had greater HDL-c concentration than 110%-1 RM group after 48 h (p = 0.05) and 72 h (p = 0.004), respectively. Finally, The 50% group has showed lesser LDL-c concentration than 110% group after 24 h (p = 0.007). No significant difference was found in Total Cholesterol concentrations.

CONCLUSION

These results indicate that the acute resistance exercise may induce changes in lipid profile in a specific-intensity manner. Overall, low and moderate exercise intensities appear to be promoting more benefits on lipid profile than high intensity. Long term studies should confirm these findings.

Resistance training improves cardiovascular risk factors in obese women despite a significative decrease in serum adiponectin levels

Increased circulating adiponectin and insulin sensitivity are usually observed after body fat loss induced by a weight-loss diet. Progressive resistance training (PRT) without a concomitant weight-loss diet significantly decreases visceral fat, thus improving insulin sensitivity. Therefore, the purpose of this study was to ascertain the effects of combined 16-week PRT and weight-loss diet on circulating adiponectin and insulin sensitivity index. Thirty-four obese (BMI: 30-40 kg/m(2)) women, aged 40-60 year, were randomized to three groups: a control group (C; n = 9); a diet group (WL; n = 12) with a caloric restriction of 500 kcal/d; and a diet plus resistance training group (WL+RT; n = 13) with the same caloric restriction as group WL and a 16-week supervised whole body PRT of two sessions/week. Both WL and WL+RT groups showed similar decreases in body mass (-6.3% and -7.7%) and visceral fat (-19.9% and -20.5%). WL resulted in an expected increase in circulating levels of adiponectin (P = 0.07) and insulin sensitivity. However, circulating total adiponectin decreased (P < 0.05) in WL+RT group, whereas an improvement in different cardiovascular risk factors (insulin sensitivity, low-density lipoprotein cholesterol (LDL-C), etc.) was observed. In conclusion, in obese women a 16-week combined PRT and weight-loss diet is accompanied by significant improvements in different cardiovascular risk factors in spite of a significant decrease of circulating adiponectin.

Regular exercise and plasma lipid levels associated with the risk of coronary heart disease: a 20-year longitudinal study

We investigated the effects of regular exercise on the plasma lipid levels that contribute to coronary heart disease (CHD), of 20 sedentary men who participated in an exercise program over 20 consecutive years. The men, whose initial ages ranged from 30-51 years, participated in the University of Nevada-based exercise program for an average of 45 min/day, 3.5 days/week. The study examined plasma levels of low-density lipoprotein (LDL) cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), total cholesterol (TC), triglycerides (TG), and TC to HDL-C (TC/HDL-C) ratios. All lipid values improved significantly during the study (p < .05). The largest changes occurred during the first year of participation and slow, gradual improvements continued in the subsequent years. We concluded that regular exercise has positive effects on plasma lipid levels, which results in reducing the risk of CHD in middle-aged and older adults.

Resistance training with soy vs whey protein supplements in hyperlipidemic males

Background

Most individuals at risk for developing cardiovascular disease (CVD) can reduce risk factors through diet and exercise before resorting to drug treatment. The effect of a combination of resistance training with vegetable-based (soy) versus animal-based (whey) protein supplementation on CVD risk reduction has received little study. The study's purpose was to examine the effects of 12 weeks of resistance exercise training with soy versus whey protein supplementation on strength gains, body composition and serum lipid changes in overweight, hyperlipidemic men.

Methods

Twenty-eight overweight, male subjects (BMI 25–30) with serum cholesterol >200 mg/dl were randomly divided into 3 groups (placebo (n = 9), and soy (n = 9) or whey (n = 10) supplementation) and participated in supervised resistance training for 12 weeks. Supplements were provided in a double blind fashion.

Results

All 3 groups had significant gains in strength, averaging 47% in all major muscle groups and significant increases in fat free mass (2.6%), with no difference among groups. Percent body fat and waist-to-hip ratio decreased significantly in all 3 groups an average of 8% and 2%, respectively, with no difference among groups. Total serum cholesterol decreased significantly, again with no difference among groups.

Conclusion

Participation in a 12 week resistance exercise training program significantly increased strength and improved both body composition and serum cholesterol in overweight, hypercholesterolemic men with no added benefit from protein supplementation.

Effects of aquatic resistance training on health and fitness in postmenopausal women

To investigate effects of 24 weeks of resistance training with aquatic resistance devices or elastic bands (EB) on markers of cardiovascular health and physical capacity. Forty-six healthy, sedentary postmenopausal women participated. The groups were aquatic exercise (AE; n = 15), EB (n = 21), and control (n = 10). Venous blood chemistry included cholesterol, triglycerides, glucose, and apolipoprotein B. Physical capacity was assessed by the sit-and-reach, knee push-up, 60-s squat, and abdominal crunch tests. Both AE and EB, respectively, showed a significant (P <or= 0.05) decrease in body fat (14.56, 11.97%) and diastolic blood pressure (8.03, 5.88%), and a significant increase in fat-free mass (2.88, 1.22%), sit-and-reach (27.94, 44.2%), knee push-ups (84.74, 51.59%), and 60-s squats (65.76, 46.04%). AE also showed a significant increase in abdominal crunches (28.11%). Aquatic resistance training can offer significant physiological benefits in health and performance that are comparable to those obtained from EB in this population.

Lipid metabolism in young men after acute resistance exercise at two different intensities

The aim of this study was to examine the effects of different resistance training loads on blood lipids. Six healthy, untrained male volunteers performed three protocols: control (no exercise), high intensity (HI) and low intensity (LI) exercise seven days apart. Each protocol comprised eight exercises. The HI protocol used a 10-repetition maximum (RM) load and 10 repetitions. In the LI protocol, the load was halved and repetitions doubled. The volume of work performed in the two exercise protocols was identical. Blood samples were collected before, immediately after, and 15 min after each protocol and analysed for total, high density (HDL-C), low density cholesterol and triglyceride. The only significant effect of exercise was to acutely increase HDL-C in the immediate post exercise sample compared with the control. There was no significant effect on any lipid fraction resulting from the LI protocol compared with the control. The results of this study suggest that intensity alone has an effect in determining the HDL-C response to acute resistance exercise.

Effects of endurance training and resistance training on plasma lipoprotein profiles in elderly women

It has been shown that high levels of high-density lipoprotein (HDL) cholesterol and low levels of low-density lipoprotein (LDL) cholesterol are associated with health maintenance in older women, but the few studies that have examined the relationship between exercise and plasma lipoprotein levels in this elderly population have been equivocal. In addition, there are no studies that examine the plasma lipoprotein response of two different types of exercise in a group of active but nonexercising women. Thus, the effects of exercise training on plasma lipoprotein levels in elderly women remain unclear. The purpose of this research was to examine the effects of endurance and resistance exercise on plasma lipoprotein levels in elderly women who were active but nonexercising prior to the study. A total of 45 healthy, active women, aged 70-87 years, were randomly assigned to either an aerobic training (AT, 76 +/- 5 years, n = 15), resistance training (RT, 73 +/- 3 years, n = 15), or control (C, 74 +/- 5 years, n = 15) group. The AT group walked 3 days a week at 70% heart rate reserve. The duration on day 1 was 20 minutes, and it was increased by 5 minutes each day until subjects were walking for 50 minutes (week 3). The exercise training session for the RT group consisted of one to three sets of eight repetitions of eight different exercises at an eight repetition maximum; the C group maintained normal activity. Weight and diet were unchanged across groups. The exercise interventions lasted 10 weeks. Blood samples were obtained from all subjects at week 0 and week 11. Training resulted in a significant decrease in 1-mile walk times and heart rate at completion of the walk for the AT group and a significant increase in eight repetition maximum of all RT exercises. Both AT and RT groups experienced increased HDL cholesterol and decreased triglycerides at week 11 compared with week 0. There were no positive changes in control lipoproteins. Both triglycerides and the total cholesterol to HDL ratio increased significantly while total cholesterol, HDL cholesterol, and LDL cholesterol remained unchanged. The RT group also had significantly lower LDL cholesterol and total cholesterol compared with controls at week 11. Both RT and endurance training resulted in favorable changes to plasma lipoprotein levels for elderly women in only 10 weeks. The fact that this occurred without concurrent changes in weight or diet is an indication that high-intensity exercise alone can be used to modify lipoproteins in populations of healthy elderly women.

Blood lipid and lipoprotein adaptations to exercise: a quantitative analysis

Dose-response relationships between exercise training volume and blood lipid changes suggest that exercise can favourably alter blood lipids at low training volumes, although the effects may not be observable until certain exercise thresholds are met. The thresholds established from cross-sectional literature occur at training volumes of 24 to 32 km (15 to 20 miles) per week of brisk walking or jogging and elicit between 1200 to 2200 kcal/wk. This range of weekly energy expenditure is associated with 2 to 3 mg/dl increases in high-density lipoprotein-cholesterol (HDL-C) and triglyceride (TG) reductions of 8 to 20 mg/dl. Evidence from cross-sectional studies indicates that greater changes in HDL-C levels can be expected with additional increases in exercise training volume. HDL-C and TG changes are often observed after training regimens requiring energy expenditures similar to those characterised from cross-sectional data. Training programmes that elicit 1200 to 2200 kcal/wk in exercise are often effective at elevating HDL-C levels from 2 to 8 mg/dl, and lowering TG levels by 5 to 38 mg/dl. Exercise training seldom alters total cholesterol (TC) and low-density lipoprotein-cholesterol (LDL-C). However, this range of weekly exercise energy expenditure is also associated with TC and LDL-C reductions when they are reported. The frequency and extent to which most of these lipid changes are reported are similar in both genders, with the exception of TG. Thus, for most individuals, the positive effects of regular exercise are exerted on blood lipids at low training volumes and accrue so that noticeable differences frequently occur with weekly energy expenditures of 1200 to 2200 kcal/wk. It appears that weekly exercise caloric expenditures that meet or exceed the higher end of this range are more likely to produce the desired lipid changes. This amount of physical activity, performed at moderate intensities, is reasonable and attainable for most individuals and is within the American College of Sports Medicine's currently recommended range for healthy adults.

Potential health-related benefits of resistance training

Public health guidelines primarily focus on the promotion of physical activity and steady-state aerobic exercise, which enhances cardiorespiratory fitness and has some impact on body composition. However, research demonstrates that resistance exercise training has profound effects on the musculoskeletal system, contributes to the maintenance of functional abilities, and prevents osteoporosis, sarcopenia, lower-back pain, and other disabilities. More recent seminal research demonstrates that resistance training may positively affect risk factors such as insulin resistance, resting metabolic rate, glucose metabolism, blood pressure, body fat, and gastrointestinal transit time, which are associated with diabetes, heart disease, and cancer. Research also indicates that virtually all the benefits of resistance training are likely to be obtained in two 15- to 20-min training sessions a week. Sensible resistance training involves precise controlled movements for each major muscle group and does not require the use of very heavy resistance. Along with brief prescriptive steady-state aerobic exercise, resistance training should be a central component of public health promotion programs.

Examining the validity of exercise guidelines for the prevention of morbidity and all-cause mortality

Public health guidelines focus on increasing low to moderate physical activity levels in a largely sedentary population. While there is some evidence that inactivity is associated with increased risk of morbidity and mortality, there appears to be much stronger and consistent evidence for a graded inverse relationship between physical fitness and morbidity and mortality. However, epidemiological studies investigating physical fitness have often not directly measured aerobic capacity. This calls into question the specific recommendations that assume a direct relationship between aerobic capacity and risk. Performance on some test protocols can be favorably affected by increases in strength and musculoskeletal changes, in addition to aerobic capacity. Other public health recommendations assume that the volume of training, the total amount of work, or caloric expenditure is the key stimulus for health-protective adaptations. However, there is little evidence to support this long-held axiom. A balance of resistance training and aerobic training is recommended for decreasing morbidity and mortality. A threshold theory of adaptation and training is proposed that potentially can efficiently and effectively enhance aerobic capacity and strength in minimal time.

Resistance exercise training reduces hypertriglyceridemia in HIV-infected men treated with antiviral therapy

Hypertriglyceridemia, peripheral insulin resistance, and trunk adiposity are metabolic complications recently recognized in people infected with human immunodeficiency virus (HIV) and treated with highly active antiretroviral therapy (HAART). These complications may respond favorably to exercise training. Using a paired design, we determined whether 16 wk of weight-lifting exercise increased muscle mass and strength and decreased fasting serum triglycerides and adipose tissue mass in 18 HIV-infected men. The resistance exercise regimen consisted of three upper and four lower body exercises done for 1-1.5 h/day, 4 days/wk for 64 sessions. Dual-energy X-ray absorptiometry indicated that exercise training increased whole body lean mass 1.4 kg (P = 0.005) but did not reduce adipose tissue mass (P = NS). Axial proton-magnetic resonance imaging indicated that thigh muscle cross-sectional area increased 5-7 cm(2) (P < 0.005). Muscle strength increased 23-38% (P < 0.0001) on all exercises. Fasting serum triglycerides were decreased at the end of training (281-204 mg/dl; P = 0.02). These findings imply that resistance exercise training-induced muscle hypertrophy may promote triglyceride clearance from the circulation of hypertriglyceridemic HIV-infected men treated with antiviral therapy.

Strength training does not alter the effects of testosterone propionate injections on high-density lipoprotein cholesterol concentrations

The purpose of the study was to examine the long-term effects of a high-volume strength training program (vertical ladder climbing) and testosterone propionate injections (intraperitoneal) on serum lipid and lipoprotein concentrations in male Sprague-Dawley rats. The animals were randomly divided into a testosterone (T)-treated group (dose per injection, 2.5 mg/kg testosterone propionate solubilized in 1 mL safflower oil) and a control (C) group (injected with an isovolumic amount of safflower oil alone). Animals were further divided into a strength-trained group (E) and a sedentary group (S). The 10-week resistance training program consisted of weights (100% of body mass) appended to the tail as the animal climbed an 85-cm ladder to volitional fatigue. Following 10 weeks of strength training and testosterone injections, body weight was not significantly different between the main effects of strength training exercise (TE + CE v TS + CS) and testosterone injections (TE + TS v CE + CS) or between groups. Testicular mass (mean +/- SE) was measured as a relative indicator of testosterone effects. Both TE and TS had significantly reduced testicular mass (2.56 +/- 0.04 and 2.38 +/- 0.03 g, respectively) compared with CE and CS (3.49 +/- 0.03 and 3.49 +/- 0.04 g, respectively). No significant differences were observed between groups for total serum cholesterol, serum triglycerides, or serum low-density lipoprotein cholesterol (LDL-C). In contrast, significant decreases in high-density lipoprotein cholesterol (HDL-C) were observed for both TE (26.7 +/- 1.6 mg/dL) and TS (27.5 +/- 1.3 mg/dL) compared with CE (48.7 +/- 2.9 mg/dL) and CS (43.5 +/- 2.6 mg/dL). As a result, the total cholesterol to HDL-C ratio was significantly greater for TS + TE (4.7 +/- 0.1) compared with CS + CE (2.9 +/- 0.2). These observations suggest that in animals, a 10-week program of high-volume strength training does not elicit any beneficial effect on the lipid or lipoprotein status, nor does it attenuate the altered lipoprotein profile induced by testosterone propionate injections.

Differential effect of resistance training on the body composition and lipoprotein-lipid profile in older men and women

The effects of a 12-week resistance exercise training (RT) program on body composition and serum lipid concentrations were assessed in weight-stable, moderately overweight older men (n = 18) and women (n = 17) aged 54 to 71 years with a body mass index (BMI) of 26 to 36 kg/m2. Following RT, the men had a significant increase in fat-free mass (FFM) and a decrease in percent body fat (%BF) and fat mass (FM), whereas the women demonstrated no change, resulting in significant time-by-sex interactions for FFM (P = .002), %BF (P = .006), and FM (P = .005). There were no changes in total cholesterol (Chol), low-density lipoprotein cholesterol (LDL-C), or triacylglycerol (Tg) due to RT. However, following RT, high-density lipoprotein cholesterol (HDL-C) increased (0.06+/-0.02 mmol/L) in the men and decreased (0.09+/-0.03 mmol/L) in the women (time-by-sex interaction, P = .0004). The Chol/HDL-C ratio decreased (0.36+/-0.11) in the men and increased (0.29+/-0.10) in the women (time-by-sex interaction, P = .0001). For all subjects combined, the changes in HDL-C and the Chol/HDL-C ratio were not related to any changes in body fat stores (ie, %BF or FM), suggesting that RT may potentially alter the lipoprotein-lipid profile in older weight-stable men and women. In conclusion, although the changes in the lipoprotein-lipid profile were small, the men had a significantly increased HDL-C level and decreased Chol/HDL-C ratio, while the women demonstrated opposite changes.

Exercise training and blood lipids in hyperlipidemic and normolipidemic adults: a meta-analysis of randomized, controlled trials

OBJECTIVE

To determine the effectiveness of exercise training (aerobic and resistance) in modifying blood lipids, and to determine the most effective training programme with regard to duration, intensity and frequency for optimizing the blood lipid profile.

DESIGN

Trials were identified by a systematic search of Medline, Embase, Science Citation Index (SCI), published reviews and the references of relevant trials. The inclusion criteria were limited to randomized, controlled trials of aerobic and resistance exercise training which were conducted over a minimum of four weeks and involved measurement of one or more of the following: total cholesterol (TC), high density lipoprotein (HIDL-C), low density lipoprotein (LDL-C) and triglycerides (TG).

SUBJECTS

A total of 31 trials ( 1833 hyperlipidemic and normolipidemic participants) were included.

RESULTS

Aerobic exercise training resulted in small but statistically significant decreases of 0.10 mmol/L (95% CI: 0.02, 0.18). 0.10 (95% CI: 0.02, 0.19), 0.08 mmol/L (95% CI: 0.02, 0.14), for TC, LDL-C, and TG, respectively, with an increase in HDL-C of 0.05 mmol/L (95% CI: 0.02, 0.08). Comparisons between the intensities of the aerobic exercise programmes produced inconsistent results; but more frequent exercise did not appear to result in greater improvements to the lipid profile than exercise three times per week. The evidence for the effect of resistance exercise training was inconclusive.

CONCLUSIONS

Caution is required when drawing firm conclusions from this study given the significant heterogeneity with comparisons. However, the results appear to indicate that aerobic exercise training produced small but favourable modifications to blood lipids in previously sedentary adults.

Effect of 14 weeks of resistance training on lipid profile and body fat percentage in premenopausal women

OBJECTIVES

To study the effects of a supervised, intensive (85% of one repetition maximum (1-RM)) 14 week resistance training programme on lipid profile and body fat percentage in healthy, sedentary, premenopausal women.

SUBJECTS

Twenty four women (mean (SD) age 27 (7) years) took part in the study. Subjects were randomly assigned to either a non-exercising control group or a resistance exercise training group. The resistance exercise training group took part in supervised 45-50 minute resistance training sessions (85% of 1-RM), three days a week on non-consecutive days for 14 weeks. The control group did not take part in any structured physical activity.

RESULTS

Two way analysis of variance with repeated measures showed significant (p < 0.05) increases in strength (1-RM) in the exercising group. There were significant (p < 0.05) decreases in total cholesterol (mean (SE) 4.68 (0.31) v 4.26 (0.23) mmol/1 (180 (12) v 164 (9) mg/dl)), low density lipoprotein (LDL) cholesterol (2.99 (0.29) v 2.57 (0.21) mmol/l (115 (11) v 99 (8) mg/dl), the total to high density lipoprotein (HDL) cholesterol ratio (4.2 (0.42) v 3.6 (0.42)), and body fat percentage (27.9 (2.09) v 26.5 (2.15)), as well as a strong trend towards a significant decrease in the LDL to HDL cholesterol ratio (p = 0.057) in the resistance exercise training group compared with their baseline values. No differences were seen in triglycerides and HDL cholesterol. No changes were found in any of the measured variables in the control group.

CONCLUSIONS

These findings suggest that resistance training has a favourable effect on lipid profile and body fat percentage in healthy, sedentary, premenopausal women.

Aerobic circuit exercise training: effect on adolescents with well-controlled insulin-dependent diabetes mellitus

OBJECTIVES

To test the safety and effects of exercise conditioning on cardiorespiratory fitness, body composition, muscle strength, glucose regulation, and lipid/cholesterol levels.

SUBJECTS

Ten male adolescents with insulin-dependent diabetes mellitus (IDDM) and 10 adolescent nondiabetic (ND) subjects.

DESIGN

Pretest, posttest intervention trial with control group.

SETTING

University-based human performance laboratory.

INTERVENTION

Mixed endurance and calisthenic/strength activities performed at a rapid pace three times weekly for 12 weeks.

RESULTS

Only one subject with IDDM experienced hypoglycemia after a single exercise session. Both subject groups improved their cardiorespiratory endurance (p < .05). Lean body mass of IDDM subjects increased by 3.5% (p < .05). Subjects with and without IDDM lowered their percent body fat (p < .05 and .001, respectively). Strength improvement of IDDM subjects ranged from 13.7% (p < .001) to 44.4% (p < .01), depending upon the maneuver. Fasting blood plasma glucose for all subjects was unchanged by training, but glycosylated hemoglobin A1c of IDDM subjects was reduced by .96 percentage point (p < .05). Reductions of HbA1c benefitted subjects exhibiting poor preconditioning glycemic control. Low-density lipoprotein cholesterol was decreased in subjects with IDDM (p < .05), but not total cholesterol or triglycerides.

CONCLUSION

Adolescents with IDDM undergoing aerobic circuit training improve their cardiorespiratory endurance, muscle strength, lipid profile, and glucose regulation. Aerobic circuit training is safe for properly trained and monitored adolescent diabetics.

Skeletal muscle fiber distribution influences serum high-density lipoprotein cholesterol level

Earlier we have shown a significant positive association between muscle fiber distribution, i.e. percentage of slow-twitch (ST) fibers in the vastus lateralis muscle, and serum high-density lipoprotein cholesterol (HDL-C) level. This association may be due to the fact that ST fibers have a high capacity for oxidative energy metabolism and a high number of surrounding capillaries. These fibers have a high capacity to metabolize fatty acids liberated by lipoprotein lipase (LPL) from triglyceride-rich lipoproteins. This in turn elevates serum HDL-C levels. Thus, a high percentage of ST fibers (ST-%) may be one factor having a beneficial effect on serum HDL-C concentration. A high ST-% may also increase the likelihood that a person will become involved in an endurance type of physical activity, which further increases serum HDL-C concentration by increasing further LPL activity in the capillary bed of skeletal muscle. In this paper we present a hypothetical background of the role that ST fibers may have on serum lipid and lipoprotein profile.

Physical activity and physical fitness as protection against premature disease or death

It is known from prospective studies that the incidence of coronary heart disease (CHD) is lower in the physically active compared with the sedentary part of the population, and the rate of CHD is lower with higher fitness level. In studies where both physical activity (PA) and fitness are assessed, only fitness, and not PA, appear to be an independent predictor of mortality from CHD. It is unclear whether other fitness components than maximal oxygen uptake (Vo2max) have a beneficial effect on the rate of CHD. Further, it seems likely that there is an upper threshold of fitness (Vo2max) above which no further improvement in risk factors for CHD is found. However, most middle-aged people have fitness levels below this threshold. There is no doubt that the middle-aged sedentary person benefits from physical activity regardless of type and intensity, and it may be easier to motivate a sedentary person to carry out moderate physical activity. However, it is likely that the best effect is achieved by performing physical activity of a type and intensity sufficient to improve the fitness level. Still, recommendations of type, frequency, duration and intensity are matters of debate.

Specificity in the relationship between training and performance in triathlons

The present study examines whether swim, cycle, and run performance during a triathlon are predicted best by training in the same sport, as suggested by the theory of specificity for the relationship between sport training and performance. Using behavioral measures of training (pace, mileage, workouts), multiple regression analyses of questionnaire responses from 624 triathletes (443 men, 181 women) showed pace of training in the same sport to be the best predictor of swim and run performance for both sprint and endurance triathlons. No clear patterns were seen for cycle performance. Thus, specificity in the relationship between training and performance appears supported, especially for sports that rely more on the body (swim, run) and less on equipment (cycle).

Resistance training guidelines for individuals with diabetes mellitus

Resistance/strength training is added to an exercise regimen to create a well-rounded program that enhances muscular conditioning and improves health, physical fitness, and/or athletic performance. This article presents resistance training guidelines for individuals with diabetes mellitus, with and without vascular complications. The existing literature concerning exercise prescription and the acute and chronic physiological responses to resistive-type exercise is discussed. The educator is provided with principles that govern resistance training so that safe and effective programs can be prescribed for individuals with diabetes.

A review of the effects of resistance training for individuals with diabetes mellitus

Although the effectiveness of exercise as a treatment modality for the management of diabetes mellitus has long been recognized, a vital component of the exercise prescription has been overlooked. In addition to endurance training, resistance training may provide physiologic benefits to the individual with diabetes that, in some cases, may equal or exceed those gained through aerobic training. These benefits may include improved blood lipid profiles, increased absolute left ventricular wall contractility, decreased resting blood pressure, improved insulin sensitivity and glucose tolerance, improved glycemic control, improved muscular strength and endurance, and increased bone and connective tissue strength. By utilizing a combination of aerobic and resistance training, the individual with diabetes experiences a more comprehensive exercise program that can improve most areas of health and physical fitness. In addition, having a greater number of exercise modality options may enhance exercise compliance.

Resting energy metabolism and cardiovascular disease risk in resistance-trained and aerobically trained males

The objectives of this study were (1) to examine differences in resting metabolic rate (RMR) and cardiovascular risk factors among aerobically trained (n = 36), resistance-trained (n = 18), and untrained (n = 42) young males; and (2) to investigate the influence of body composition, dietary intake, and VO2max as possible modulators of differences in cardiovascular risk among groups. Results showed that RMR, adjusted for differences in fat-free weight (FFW), was 5% higher in aerobically trained males compared with resistance-trained males (P < .01), and 10% higher than that in untrained males (P < .01). Plasma levels of cholesterol and low-density lipoprotein cholesterol (LDL-C) were comparable between resistance-trained and aerobically trained males, but were lower (P < .05) than those in untrained males. (The percent intake of dietary fat was related to plasma cholesterol [r = .32, P < .01] and LDL-C [r = .30, P < .01].) When compared with untrained males, fasting triglyceride (TG) levels were 39% and 43% lower (P < .01) in resistance-trained and aerobically trained males, respectively. When compared with untrained males, the fasting insulin to glucose ratio (I/G) was 45% and 53% lower (P < .01) in resistance- and aerobically trained males, respectively. Mean arterial pressure (MAP) was 7% lower (P < .01) in aerobically trained compared with untrained males. Statistical control for differences in percent body fat or percent intake of dietary fat diminished the differences among the groups for plasma lipids, blood pressure, and the I/G ratio. We conclude that aerobically trained and resistance-trained males have higher resting energy requirements independent of FFW compared with untrained males. Aerobically trained and resistance-trained young males have comparable and favorable cardiovascular disease risk profiles compared with untrained males, and this appears to be related to their low level of adiposity and low intake of dietary fat.

Relationship of skeletal muscle fiber type to serum high density lipoprotein cholesterol and apolipoprotein A-I levels

We measured the percentage of slow-twitch (ST) muscle fibers in the lateral portion of the quadriceps femoris muscle in 41 healthy sedentary male controls, 35 active male joggers, and 26 male coronary heart disease (CHD) patients. We then compared these percentages with serum levels of total cholesterol (TC), triglycerides (TG), high density lipoprotein cholesterol (HDL-C) and apolipoprotein A-I (apo A-I) found in these 102 middle-aged men. The percentage of ST muscle fibers in all men correlated positively with serum HDL-C (r = 0.57, P less than 0.001) and with apo A-I (r = 0.60, P less than 0.001) and negatively with triglycerides (r = -0.43, P less than 0.001). The proportion of ST fibers in joggers (65%; 61-69%, 95% confidence interval) was higher (P less than 0.001) than in sedentary controls (48%; 44-52%) or in CHD patients (44%; 39-49%). Moreover, 89% of the joggers had a proportion of ST fibers higher than 50%, whilst in sedentary controls and in CHD patients these values were 46% and 38%, respectively. Positive correlations were found between the percentage of ST fibers and both HDL-C and apo A-I in controls (r = 0.33, P less than 0.05 and r = 0.34, P less than 0.05) and in joggers (r = 0.46, P less than 0.01, and r = 0.40, P less than 0.05), respectively. Negative correlations in controls (r = -0.34, P less than 0.05) and in CHD patients (r = -0.43, P less than 0.05) were also found between the percentage of ST fibers and serum TG.(ABSTRACT TRUNCATED AT 250 WORDS)

Lipid profile of body builders with and without self-administration of anabolic steroids

Twenty-four top-level body builders [13 anabolic steroid users (A); 11 non-users (N)] and 11 performance-matched controls (C) were examined to determine the effect on lipids, lipoproteins and apolipoproteins of many years of body building with and without simultaneous intake of anabolic steroids and testosterone. After an overnight fast, triglycerides (TG), total cholesterol (TOTC), high density lipoprotein cholesterol (HDLC), low density lipoprotein cholesterol (LDLC), the HDLC subfractions HDL2C and HDL3C, as well as apolipoprotein A-I (Apo A-I), apolipoprotein A-II (Apo A-II) and apolipoprotein B (Apo B) were determined. Both A and N, compared to C, showed significantly lower HDLC and higher LDLC concentrations, with the differences between A and C clearly pronounced. In a subgroup of 6 body builders taking anabolic steroids at the time of the study, HDLC, HDL2C, HDL3C, Apo A-I and Apo A-II were all significantly lower and LDLC was significantly higher than in a second subgroup of 7 body builders who had discontinued their intake of anabolic steroids at least 4 weeks prior to the study. In some single cases HDLC was barely detectable (2-7 mg.dl-1). The TG and TOTC remained unchanged. The present findings suggest that many years of body building among top-level athletes have no beneficial effect on lipoproteins and apolipoproteins. Simultaneous use of anabolic steroids results in part in extreme alterations in lipoproteins and apolipoproteins, representing an atherogenic profile. After discontinuing the use of anabolic steroids, the changes in lipid metabolism appear to be reversible.