The effect of acute exercise on high density lipoprotein-cholesterol and the subfractions in females.

The effect of an acute exercise session on high density lipoprotein-cholesterol (HDL-C) and the subfractions HDL2-C and HDL3-C was determined for 9 healthy females (VO2max = 46.62 +/- 4.82 ml X kg-1 min-1). Each subject underwent a continuous 40-min run on a treadmill at a workload corresponding to 70% of VO2max. A venous blood sample was obtained immediately prior to exercise and 5 min, 24, 48 and 96 h after the exercise. Pre-exercise values were: HDL-C (61.7 +/- 3.7 mg X dl-1); HDL2-C (22.4 +/- 2.1 mg X dl-1); HDL3-C (39.3 +/- 2.0 mg X dl-1). At 5 min after exercise, HDL-C (66.2 +/- 4.4 mg X dl-1) and HDL3-C (44.5 +/- 2.8 mg X dl-1) were significantly elevated (P less than 0.01) when compared to pre-exercise values. HDL-C and HDL3-C were not significantly different from pre-exercise at the remaining time points. In comparison with pre-exercise, HDL2-C showed no significant change at any of the post-exercise time points. Results indicated that the rise in HDL-C following acute exercise was due to an increase in the subfraction HDL3-C. The change in total HDL-C and HDL3-C was transient in that pre-exercise values were re-attained within 24 h following acute submaximal exercise.

Effects of acute smoking and exercise on high-density lipoprotein-cholesterol and subfractions in black female smokers.

This study investigated the effects of acute bouts of both exercise and smoking on high-density lipoprotein-cholesterol subfractions, HDL2-C and HDL3-C in black females. During two testing trials, seven subjects were exposed to either acute exercise or smoking. Treadmill exercise was performed at 70% of heart rate reserve for 15 minutes. Blood samples were taken before, immediately after, and 10 minutes after exercise. The smoking trial consisted of subjects smoking two cigarettes followed by 30 minutes of nonsmoking. Blood samples were taken before smoking, after each cigarette, and after two 15-minute intervals of nonsmoking. The exercise protocol resulted in a 10.8% increase in total HDL-C, primarily through an increase in the HDL2-C subfraction. The values returned to baseline within 10 minutes after exercise. Smoking one cigarette decreased total HDL-C by 10%. Neither subfraction was significantly effected by smoking; however, the HDL3-C subfraction was decreased 11% and HDL2-C subfraction was decreased 14.7% from resting values. The maximum reduction in HDL3-C subfraction occurred after the smoking of the first cigarette, while the maximum reduction in the HDL2-C subfraction occurred after the first 15-minute nonsmoking period. Acute cigarette smoking was associated with a decrease in total HDL-C that was maintained through 15 minutes of nonsmoking. It is suggested that the adverse effect on HDL-C by acute smoking is a significant contributor to coronary heart disease (CHD) risk in black females. Results further indicate that low-intensity exercise is capable of transiently increasing the total HDL-C via an increase in the anti-atherogenic HDL2-C subfraction.(ABSTRACT TRUNCATED AT 250 WORDS)

Progressive strength training in sedentary, older African American women.

PURPOSE: This study investigated effects of an 8-wk, low-frequency and low-volume, supervised, progressive strength training program emphasizing free weight, multijoint movements on the muscular power, strength, endurance, and flexibility of African American women 44 to 68 yr of age. METHODS: Nineteen sedentary African American women were randomly assigned to a strength training (ST) only group (N = 12; mean age, 51 yr) or a nonexercise control (C) group (N = 7; mean age, 52 yr). Maximal power, strength, absolute endurance, and flexibility were assessed before and after training. Subjects trained 2 d x wk(-1) using free weight (barbells and dumbbells) and machine (plate loaded) exercises for two to three sets of 8 to 10 repetitions on both primary and assistance exercises. RESULTS: Upper body power (medicine ball put distance) significantly increased statistically (P = 0.002), but gains possibly lacked practical significance because of measurement variation. Lower body power (peak watts on bicycle) experienced a small, nonsignificant increase in the ST group. Significant increases (P = 0.000) in 1RM muscle strength occurred in the ST group (leg press, +99.8%; bench press, +34.4%). Absolute endurance significantly increased (P = 0.000) in the ST group (leg press repetitions to failure at 70% pretest 1RM, +221%; bench press repetitions to failure at 50% pretest 1RM, +112%). Significant flexibility gains occurred in the ST group (sit-and-reach test, +8.2%; P = 0.017). No significant changes occurred in power, strength, absolute endurance, or flexibility in the C group. CONCLUSION: This study demonstrates that 8 wk of low-frequency, supervised, progressive strength training emphasizing free weight, multijoint movements can safely cause significant gains in muscle strength, absolute endurance, and flexibility in older African American women.

Effect of blood pH on peripheral and central signals of perceived exertion.

Ten male subjects underwent exercise testing in three modes, arms (A), legs (L), and arms + legs (A + L), after ingesting 0.3 g X kg-1 body weight of either NaHCO3 to induce alkalosis or CaCO3 as a placebo (i.e., six exercise trials). Ratings of perceived exertion (RPE: Borg, 15-pt scale) for the arms (RPE-A), legs (RPE-L), chest (REP-C), and overall body (RPE-O) did not differ between acid-base conditions at 20, 40, or 60% VO2max for all three exercise modes. At 80% VO2max, 1) RPE-A was lower (P less than 0.01) during A; 2) RPE-L was lower (P less than 0.01) during L; and 3) RPE-A and RPE-L were lower (P less than 0.01) during A + L under the NaHCO3 as compared to the CaCO3 condition. Differences were not found for RPE-L during A or for RPE-A during L. RPE-C and RPE-O were lower (P less than 0.01) under NaHCO3 during A, L, and A + L. Blood acid-base, VO2, and cardiorespiratory responses were not differentially influenced by exercise mode. Blood pH was significantly higher under NaHCO3 than CaCO3 at pre-exercise and 80% VO2max. VO2, heart rate, and tidal volume did not differ between acid-base conditions at any exercise intensity. VE and respiratory rate did not differ between acid-base conditions at 20, 40, or 60% VO2max but were significantly lower under NaHCO3 at 80% VO2max. RPE-A and L were positively related to blood [H+], and RPE-C was positively related to VE for all exercise modes.

Eight Programs to Consider.

Exercise videos allow patients to improve overall fitness in the comfort of their own homes. But cutting through the Hollywood glitz and hype that surround this lucrative fitness market is difficult. Here are one exercise physiologist's recommendations for exercise videos for patients at various fitness levels.

Efficacy of moist heat pack application over static stretching on hamstring flexibility.

Inadequate flexibility is a contributing factor to muscle injury, especially with respect to the hamstring muscle group. Simple therapeutic regimens capable of increasing hamstring flexibility may reduce the injury potential of athletes with below-average hamstring flexibility or history of injury. This study compared 30 seconds of static stretching with 20 minutes of heat application on hamstring flexibility. A secondary purpose was to determine the relationship between the subjects attitude toward each treatment and the efficacy of treatment. Thirty undergraduate student athletes who were current members of a Midwestern collegiate football team participated in a 2 (treatment: heat vs. stretching) by 2 (coun-terbalanced order: heat first vs. stretching first) repeated-measures design. Results indicated that significant benefits to increase hamstring flexibility could be gained by using moist heat packs in comparison with static stretching despite a perceived attitudinal bias in favor of stretching. These findings may have implications for orthopedic fitness as well as injury prevention for an athlete with prior hamstring injury or inadequate flexibility.

Injuries and muscle soreness during the one repetition maximum assessment in a cardiac rehabilitation population.

BACKGROUND: Strength training (ST) may be beneficial for preservation of lean tissue, increasing bone mineral content, decreasing falls, and enhancing quality of life. Strength training is becoming an appropriate mode of exercise for cardiac rehabilitation (CR) patients. One method for determining optimal exercise intensity for safe and effective ST requires one repetition maximum (1RM) testing. Clinicians may be reluctant to perform 1RM testing in CR patients because of potential muscle soreness/injury and adverse hemodynamic responses in deconditioned patients. The purpose of this investigation was to perform 1RM testing in CR patients and determine muscle soreness/injury rate. METHODS: Seventy-four CR patients stratified by risk (low n = 30, intermediate n = 21, high n = 23) and sex (males = 55, females = 19) participated. Subject's ages ranged from 39 to 76 years and time from procedure ranged from 19 days to 2 years. No patient had ever undergone 1RM testing. The method of Kraemer and Fry was used to assess 1RM. High-risk patients' heart rates/rhythms and blood pressures were monitored. Patients were evaluated for occurrence of muscle soreness/injury immediately after 1RM testing and on days 2 and 7 using a soreness scale developed by Shaw et al. Muscle soreness/injury was considered significant if a patient reported altering or stopping physical activities. RESULTS: No injury or significant muscle soreness occurred as a result of 1RM testing. No abnormal heart rate/rhythm or blood pressure responses occurred in high-risk patients. CONCLUSIONS: Results indicate that with proper technique, 1RM testing may be performed in CR patients without injury or significant muscle soreness.

Development of a branching submaximal treadmill test for predicting VO2max.

This study determined the reliability and validity of a branching treadmill protocol in predicting VO2max. Thirty-seven, apparently healthy individuals (19 women and 18 men); volunteered to participate. On 2 separate testing days, each subject underwent maximal exercise testing using the protocol developed. Stepwise regression analysis indicated that the percentage of age-predicted maximum heart rate (APMHR) achieved at stage 3, speed and grade at stage 3, and APMHR accounted for 89% of the variance in VO2max. The 4 predictor variables were statistically significant (p < 0.01), and the standard error of the estimate was 4.56 ml x kg(-1) min(-1). Results indicate that health and fitness professionals can incorporate this protocol into their practices for the purpose of predicting VO2max for their clients outside the laboratory environment. Furthermore, our results indicate that using the proposed regression model is reliable and has received preliminary construct validity support.

Cardiopulmonary responses, muscle soreness, and injury during the one repetition maximum assessment in pulmonary rehabilitation patients.

PURPOSE: The safety of one repetition maximum (1RM) testing for patients with chronic obstructive pulmonary disease (COPD) has not been determined. Therefore, this study was conducted to determine the prevalence of abnormal cardiopulmonary responses, muscle soreness, and muscle injury of patients with moderate to severe COPD in response to 1RM testing. METHODS: Twenty pulmonary rehabilitation patients (11 women and 9 men) with moderate or severe COPD participated in this investigation. The 1RM testing was performed using the parallel squat and incline press. Blood pressure, heart rate dyspnea ratings, and oxygen saturation responses were measured immediately following the 1RM procedure. Ratings of muscle soreness and injury were measured immediately after 1RM testing and on days 2 and 7. RESULTS: No injury, significant muscle soreness, or abnormal cardiopulmonary responses occurred as a result of 1RM testing. No gender differences were found for any variable measured in response to 1RM testing. CONCLUSIONS: A properly supervised and screened pulmonary rehabilitation population can be 1RM tested without significant muscle soreness, injury, or abnormal cardiopulmonary responses.

Combined high-intensity strength and aerobic training in diverse phase II cardiac rehabilitation patients.

BACKGROUND: Developing adequate levels of muscular strength in the cardiac rehabilitation (CR) patient helps return the patient to an active lifestyle. This study evaluated the effects and safety of an 8-week high-intensity strength training (ST) program combined with a traditional aerobic-based CR program on the muscular strength of a diverse phase II CR population. METHODS: Sixty-one phase II CR patients (age = 60.5 +/- 10.6 years) stratified by risk (high risk: n = 18, ejection fraction = 23.6 +/- 7.8%; intermediate risk: n = 19, ejection fraction = 40.0 +/- 4.6%; low risk: n = 24, ejection fraction = 58.0 +/- 7.7%) and gender (males = 46, females = 15) participated. One repetition maximum (1RM) testing was performed on the horizontal squat, shoulder press, leg extension, lat pulldown, and biceps curl. Patients performed two sets of each exercise 2 days per week at an intensity that started at 60% 1RM and progressed to 80% 1RM by week 4. Weeks 4 to 8 intensity was adjusted individually to maintain 8RM per set. Blood pressure and heart rate/rhythm responses to 1RM testing were monitored in high-risk patients. Muscle soreness and injury were monitored for all patients immediately after 1RM testing and on days 2 and 7. RESULTS: All patient groups made significant gains (P < 0.05) in muscle strength (mean increase: lower body = 15.3%, upper body = 16.7%). No injury or significant muscle soreness occurred due to 1RM testing. No abnormal heart rate/rhythm or blood pressure responses occurred in high-risk patients. CONCLUSIONS: Diverse phase II CR patients can improve their strength significantly with a combination of high-intensity strength and aerobic training.