ABSTRACTIsokinetics remains a popular form of resistance in the clinical setting for orthopedic rehabilitation; however, little is known about its effect on the cardiovascular system. The present study was designed to describe the acute cardiovascular responses to isokinetic exercises at 3 different

PURPOSE:The purpose of this study was to compare the metabolic and cardiovascular responses of movement in forward (FM), backward (BM), and lateral (LM) directions. METHODS:Thirteen athletes with the following characteristics (mean +/- SD) were evaluated: age 21+/-3 yr, height 172.0+/-9.0 cm, weight 62.92+/-9.05 kg, and VO2max 54.13+/-7.42 mL x kg(-1) x min(-1). Subjects were evaluated at 80.45 and 134.08 m x min(-1). A repeated measures ANOVA was used for statistical analysis (P < 0.05). RESULTS:At 80.45 m x min(-1), the following respective VO2 mL x kg(-1) x min(-1) and heart rate (HR) beats x min(-1) responses were: FM = 12.42+/-2.29, 113+/-10; BM = 15.95+/-2.45, 132+/-16; and LM = 22.10+/-4.76, 140+/-15. Both VO2 and HR were significantly different between conditions: LM > BM > FM. At 134.08 m x min(-1), the following respective VO2 and HR responses were: FM = 27.15+/-2.51, 146+/-7; BM = 31.33+/-5.77, 168+/-11; and LM = 32.58+/-5.74, 169+/-10. At 134.08 m x min(-1) neither HR or VO2 were significantly different between LM or BM (LM, BM, > FM). Stride length and stride frequency were also significantly different between conditions. These results indicate the variation in the energy cost of FM, BM, and LM.

The purpose of this study was to evaluate the prediction of ˙VO2 max in youth soccer players. Thirteen highly trained soccer players (mean age 12.62 ± 0.65 yrs) performed the 20 meter shuttle run test (20 MST) and a laboratory treadmill (TM) evaluation. Correlation's between directly measured ˙VO2 max and values predicted by the equations of Leger et al. (1988) were r = 0.78, SEE 3.82 for Equation (Eq) 1 (˙VO2 max = 31.025 + (3.238 * velocity max) - (3.248 * age) + (0.1536* age * velocity max) and r = 0.86, SEE = -1.39 for Eq 2(˙VO2 max = -24.4 + 6 * velocity max). A repeated measures ANOVA indicated no significant difference between measured and predicted˙VO2 max, (p > 0.05) (TM ˙VO2 max = 56.53 ± 5.80, Eq 1 ˙VO2 max = 58.68 ± 3.22, and Eq 2 ˙VO2 max = 55.14 ± 3.89. There was also no significant difference between post exercise blood lactate values (TM lactate = 6.07 ± 1.40 and 20 MST lactate = 6.26 ± 1.92 mM). It was concluded that the 20 MST was a valid predictor of ˙VO2 max.

The purpose of this study was to determine the effects of two bench-step exercise speeds on vertical impact forces and to explore this variable between novices and instructors. 12 women (mean age 24 yr.) randomly performed 8-min. protocols of the “basic” bench-stepping technique and a more advanced “travel” technique at 30 and 33 cycles · min.−1. Analysis showed that the faster exercise rate yielded significantly higher vertical impact forces on a reference (B-8) step height (20.3 cm). At 33 cycles · min.−1, the instructors' and novices' responses were both higher than those at 30 cycles · min.−1. The mean peak vertical impact force ranged from 1.54 times the body weight for the novice group at 30 cycles · min.−1 to 1.87 times the body weight for instructors at 33 cycles · min.−1. A comparison of the groups' force curves showed a distinctive pattern in the loading of the impact forces. Specifically, the instructors consistently produced a transitory decrement in force prior to attaining peak force. In addition, the novices exhibited nonuniform increases in the production of vertical impact force across other step heights at the faster (33 cycles · min.−1) speed. Thus, experience with bench-step exercise may afford an ability to make uniform and force-absorbing adjustments in the resultant vertical impact forces at increased speeds.

The purpose of this investigation was to evaluate the relationship between physical fitness items (PPI) and performance times on a fire fighter combat challenge test (CCT). Ninety-one fire fighters including 87 men and 4 women were evaluated. The mean ± SD age was 31.69 ± 7.39 yrs, height 177.29 ± 6.38 cm, weight 80.93 ± 10.86 kg, and percent fat 13.78± 4.31. The mean ± SD fitness performance scores were pull-ups 9.03 ± 4.79, push-ups 41.02 ± 14.08, 1.5 mile run 737.60± 108.11 sec, sit and reach 39.88 ± 7.75 cm, sit-ups 39.88± 7.75, and total grip strength 116.75 ± 17.67 kg. The combat challenge course included the stair climb (5 stories), hoist (hose pull), hammer (forcible entry), hose advance, and victim rescue. All tasks were completed with full turnout gear and self contained breathing apparatus(SCBA). The mean time to complete the combat challenge course was 303.54± 138.13 sec. Multiple regression analysis was performed to evaluate the relationship between the CCT and selected variables P < 0.01. The following correlation's were found between CCT time and evaluated variables: height -0.40, weight -0.30, grip strength -0.54, sit-ups -0.32, run time 0.38, push-ups -0.38, pull-ups -0.38, fat free weight (FFW) -0.47, and percent fat 0.30. The best multiple predictor of CCT time was 711.267428 + (0.506044* 1.5 mile run) - (4.735592 * FFW) - (6.546779 * pull-ups), R = 0.73 P < 0.001. Results of this investigation indicate that physical fitness related variables are significantly related to CCT performance times. The ability of a fire fighter to perform the CCT is significantly related to FFW, muscle strength, muscle endurance, and cardiovascular fitness.

The purpose of this investigation was to evaluate physiological changes and injury rates associated with lateral motion (slideboard) training. Twenty-five females performed slideboard exercise 3 days per week, 1 hour each session, over a 10 week period. Eleven females served as controls. The subjects were pre and post tested via treadmill exercise to determine VO2peak. Body composition was analyzed by a seven-site skinfold equation. The slideboard subjects (SBS) were evaluated daily for injury incidence. A factorial repeated measures ANOVA (p < 0.05) revealed a significant 14% increase in VO2peak. No significant modifications were shown for body composition. The incidence of injury was 80% for Grade I injuries, 52% for Grade II injuries, 0% for Grade III injuries, and 4% for Grade IV injuries. Thus, the primary injury reports were of a Grade I and Grade II level of severity. The present injuries were largely associated with delayed onset muscle soreness (DOMS) in the medial leg musculature during the first two weeks of training. These results show that during a 10 wk training program lateral motion exercise is an effective mode for improving cardiorespiratory fitness. In addition, the risk of incurring an injury requiring medical attention appears to be quite low. However, untrained women who perform this activity at a frequency, duration, and intensity similar to the present study may experience muscle soreness during the initial period of training.

The purpose of this investigation was to cross-validate non-exercise (N-Ex %fat and N-Ex BMI) models for predicting VO2peak in females, and to evaluate the validity of these models in estimating fitness status, based on a < 9 METs cardiovascular fitness/health-risk criterion. Subjects were 165 females who completed the PA-R activity scale and were evaluated for VO2peak and body composition. The cross-validation statistics for the N-Ex %fat and N-Ex BMI models were: ryy' = 0.86, E = 6.3 (ml.kg-1.min-1), and ryy' = 0.81, E = 6.9 (ml.kg-1.min-1), respectively. Both models were found to accurately identify 87% of the subjects with VO2peak < 9 METs. The statistics associated with the < 9 MET criterion were: ryy' = 0.73, E = 3.4 (ml.kg-1.min-1), and ryy' = 0.80, E = 4.5 (ml.kg-1.min-1), for N-Ex %fat and N-Ex BMI, respectively. The N-Ex models yielded values similar to those reported previously (Jackson, A. S., S. N. Blair, M. T. Mahar, L. T. Wier, R. M. Ross, and J. E. Stuteville. Prediction of functional aerobic capacity without exercise testing. Med. Sci. Sports Exerc. 22:863-870, 1990). When exercise testing is not an option, the present N-Ex models provide an alternative method for predicting VO2peak in females.

Previous research has shown a direct relationship between step height and vertical ground reaction forces (VGRF) during bench/step exercise. Exercise instructors commonly increase the exercise rate during bench/step instruction, but no data have been reported concerning the effect of this practice on VGRF. Therefore, the purpose of this study was to determine the effects of two bench/step exercise speeds on VGRF between novices (N) and instructors (I). Twelve females (mean age 24 yr) comprised of six N (mean BW 52.6 kg) and six I(mean BW 53.6 kg) randomly performed 5 min protocols of “basic” bench stepping at 30 and 33 cycles min-1 on 8 in steps. VGRFs were recorded at 100 HZ for 10 s by a Kistler force platform. Data were analyzed with a multi-way repeated measures ANOVA (p < 0.05) and Scheffe comparisions. Mean peak VGRF ranged from 1.56 BW for N at 30 to 1.87 BW for I at 33. The faster exercise rate yielded significanly higher VGRF. I-33, N-33> I-30, N-30 (p < 0.05). The instructors produced greater VGRF compared to the novices but this effect was not significant (p = 0.07 and 0.10 for 33 and 30, respectively). These results demonstrate that performance of bench/step exercise at a faster rate is associated with generating VGRFs that are comparable to those reported for higher steps at 30 cycles·min-1 (e. g., 10 in). While the instructors tended to generate greater peak VGRFs, a comparison of the groups' force curves revealed an empirical distinction in the pattern of loading to peak force. Specifically, the instructors consistently produced a transitory decrement in force immediately prior to attaining peak force. Apparently, bench/step exercise experience may afford an ability to anticipate peak force and thereby make compensatory (force-absorbing) adjustments in landing technique. More research in this area is indicated.

The purpose of this investigation was to evaluate the effects of a 15-week exercise training program on cardiovascular and blood lipid variables in black adolescents. Subjects consisted of black males with 12 of these participating in an exercise conditioning program and 5 designated as the control group participating in a team sports program. The mean +/- SD age was 12.8 +/- 0.97 yrs. Training for the exercise group was conducted 5 d.wk-1 for 15 weeks (weight training 2 d.wk-1 and aerobic training 3 d.wk-1). The following mean +/- SD significant changes were found for pre- to post-training for the exercise group (P < 0.05) with no significant change for controls: high density lipoprotein cholesterol (HDL-C) 1.11 +/- 0.18 to 1.28 +/- 0.17 (mmol.l-1), low density lipoprotein cholesterol (LDL-C) 2.73 +/- 0.74 to 2.41 +/- 0.81 (mmol.l-1), maximal oxygen uptake (VO2max) 43.7 +/- 9.4 to 48.2 +/- 9.7 (ml.kg-1.min-1), and maximal ventilation (VE max) 70.59 +/- 16.8 to 80.93 +/- 14.6 (L.min-1). In addition, no significant changes were found for blood pressure or other blood lipid parameters for either group. Results of this study show that exercise training can favorably alter blood lipid and VO2max values. Therefore, a vigorous exercise training program for young black males can favorably affect their cardiovascular risk profile.

It has been suggested that persons with Acute Radiation Syndrome (ARS) are prone to marked reductions in physical capacity due to the negative effects of poor physical health. To investigate whether a reduction in physical capacity could indeed be observed, 227 male subjects (age 37.5 + 5 yrs) diagnosed with ARS following the Chernobyl accident performed an annual symptom limited grade exercise test during the years 1989-1992. VO2 measurements were made during a discontinuous, incremental cycle ergometer test (50 W/4 min). Oxygen consumption was determined by open-circuit spirometry, blood pressure was obtained by auscultation and heart rate via a 12-lead EKG. Relative to physical activity, exercise was limited to light to moderate walking and cycling during the three week in-patient clinic visit each year. Mean VO2 peak was 23.8+ 3.5 ml/kg/min at year 1989 with a significant decrease noted at year 1992 (P < 0.05). A similar significant decrease (P< 0.05) was found for power output (PO) during the same time period (136W to 116W). Although not significant, reductions in MHR and SBP were also noted during the four year period. These results indicate that in this unique subject population the expected decrease in physical capacity was confirmed. In addition to the environmental radiation-induced decrement there will also be the confounding variables (biological, environmental, and psychological) that impact the physical health of this group.

Recently, slideboard exercise training has been introduced as a mode of aerobic training. The purpose of the investigation was to determine the acute cardiovascular and metabolic responses to slideboard exercise. Subjects consisted of 20 healthy females with a mean age of 26.5 +/- 7.9 years, and a VO2max of 40.8 +/- 5.6 ml.kg-1.min-1. The results of the investigation showed that 10 min of a commercially produced slideboard routine elicited mean heart rate (HR) responses ranging from 160 to 168 beats.min-1 and VO2 values of 27.5 to 33.5 ml.kg-1.min-1. A sub-group of 10 subjects was also evaluated while performing sliding exercise at different sliding rates (SR). Subjects performed the standard slide technique at metronome cadences of SR-40, SR-50, and SR-60 slide.min-1. As sliding rate increased so did HR and VO2. The subjects demonstrated mean responses of approximately 55 to 81% of VO2max for the slower to the most rapid sliding rates, respectively. Compared to treadmill exercise at the same oxygen consumption levels, the heart rates for sliding were approximately 15% higher. Slideboard exercise can be an alternative mode of aerobic training.

OBJECTIVE:The purpose of this investigation was to develop a sub-maximal exercise test for estimating VO2max utilizing aerobic dance.EXPERIMENTAL DESIGN:One hundred females between the ages 18 to 40 yr served as the subjects for test validation. The subjects completed a treadmill test to determine VO2max and were assessed for heart rate (HR) response to a bout of aerobic dance. The data associated with responses to treadmill exercise and the aerobic dance test, in conjunction with descriptive variables (e.g., age, BMI) were utilized in the validation of the multiple regression model.MEASURES:Reliability was determined by correlation and paired "t"-tests of the aerobic dance routine test and retest trials. The construction of the multiple regression equation, via forward entry analysis, and the cross-validation of the regression equation were completed to ensure the validity and reliability of the protocol in accurately estimating VO2max.RESULTS:Test, retest reliability for the dance-exercise routine was demonstrated (r = 0.98). Moreover, no significant differences were shown between the HR responses for the test and retest trials. The multiple regression analysis yielded a three variable multiple prediction equation for estimating VO2max (R = 0.84; SEE, 5.5 ml.kg-1.min-1). The three variables were the HR response to four min of aerobic dance (HR4), body mass index (BMI), and age (years). Cross-validation of the aerobic dance test was determined with a second group of 50 female subjects (R = 0.83; SEE, 5.5 ml.kg-1.min-1). Additionally, the application of the validation group regression equation to the cross-validation group yielded a comparable R of 0.82. Comparison of the predicted values for VO2max from both equations also yielded a highly significant invariance coefficient of 0.96. Finally, the results of "t"-tests between the observed and predicted mean values for VO2max revealed no significant difference (p > 0.05). Therefore, the final prediction equation, based on collapsing the means associated with the validation and cross validation samples (n = 150), was: VO2max (ml.kg-1.min-1) = 130.18-(0.38 * HR4)-(0.81 * BMI)-(0.27 * Age); R = 0.84, SEE = 5.5 ml.kg-1.min-1.CONCLUSIONS:These results indicate that a four minute aerobic dance test provides a valid and reliable sub-maximal protocol for estimating VO2max and providing an index of aerobic fitness in apparently healthy 18 to 40 yr old females.

Richards, L. A.; Williford, H. N. FACSM; Olson, M. S.; Blessing, D. L FACSM; Gauger, S.; Brown, J. Author Information

Duey, W. J.; Williford, H. N. FACSM; Wang, N.; Olson, M. S.; Blessing, D. L. FACSM; Smith, F. H. Author Information

Williford, H. N. FACSM; Richards, L. A.; Olson, M. S.; Blessing, D. L. FACSM; Gauger, S.; Brown, J. Author Information

Scharff-Obson, M.; Wilford, H. N. Jr. FACSM; Blessing, D. L FACSM; Wilson, G. O. FACSM Author Information

Blessing, D. L. FACSM; Williford, H. N. FACSM; Barksdale, J.; Wang, N.; Teel, S. Author Information

The purpose of this investigation was to determine the performance and physiologic characteristics of a "successful" American high school football team, and to compare the present values with values reported for other groups of high school, college, and professional players. For descriptive purposes, players were divided into two groups: backs (N = 8) and linemen (N = 10). Maximal aerobic power (Vo2max) was determined from a maximal treadmill test, and body composition was evaluated by hydrostatic weighing. Maximal strength values were evaluated by one-repetition maximum bench press and squat test; the sit-and-reach test was used to measure flexibility. Speed and power were evaluated by a vertical jump and a 36.6-meter sprint. Results indicate that compared with other groups of college and professional players, as the level of competition increases so do height, weight, and fat-free weight of the players. Similar maximum oxygen consumption values were found for the present group when compared with other groups of these players. From the strength and power standpoint, football players at all levels are becoming stronger. Incorporation of strength training programs has greatly improved strength and performance profiles of football players at all levels of competition.

Department of Health and Human Performance, Auburn University, Auburn, AL and Dept. of HPERD, Illinois State University, Normal, IL