Henry N. Williford

Evaluation of warm-up for improvement in flexibility

The purpose of this investigation was to evaluate the effects of warming the joints by jogging and then stretching on increases in joint flexibility. Subjects were 51 students enrolled in a physical conditioning class assigned to a jog and then stretch (JS), stretch and no jog (S), or a control group (C). Both the JS and S groups performed a series of stretching exercises 2 days a week for 9 weeks, with the JS group jogging for 5 minutes prior to stretching. Subjects were pretested and posttested for shoulder, hamstrings, trunk, and ankle flexibility with a Leighton flexometer. Results of t-tests indicated that significant increases in flexibility occurred for all of the joint angles evaluated for both the JS and S groups with the exception of trunk flexi bility for the JS group. An analysis of variance (ANOVA) of gain scores indicated a significant gain in ankle flexibility for the JS group compared to S and C groups. The S group produced a significant gain in trunk flexi bility compared to the JS group. Both JS and S groups were effective in improving flexibility, but when the gain scores were compared the results were variable. The data from this study again demonstrate that increases in flexibility can occur as a result of a static stretching training program. However, the results do not support the claim that warming the muscles prior to stretching by jogging will result in significant increases for all of the joint angles evaluated. Both methods offer possible advantages associated with improving joint flexibility.

A survey of physicians' attitudes and practices related to exercise promotion

METHODS One hundred sixty-eight physicians responded to a survey to determine their attitudes and practices related to exercise and the development of exercise prescriptions. The mean age was 45.5 +/- 10.8 years, with the majority being male (86.7%). RESULTS The survey found that 48% of the physicians required an exercise history as part of their initial examination and 91% encouraged their patients to participate in regular exercise programs. Seventy percent of the physicians did not develop exercise prescriptions and only 23% were familiar with the American College of Sports Medicine guidelines related to the development of exercise prescriptions. Only a small number of physicians (3%) had ever taken a college-level course related to exercise physiology and the development of exercise programs. The majority (78%) felt that there was a definite need in medical school for a course related to the medical aspects of exercise. CONCLUSIONS Results of this investigation indicate that while physicians support exercise for health promotion and rehabilitation, greater emphasis needs to be placed on physician involvement in promoting and/or prescribing exercise.

Relationship between fire fighting suppression tasks and physical fitness

This investigation evaluated the relationship between physical fitness and performance of fire suppression tasks. The following mean +/- SD values were associated with 91 fire fighters: age 31.69 +/- 7.39 years, height 177.29 +/- 6.38 cm, weight 83.97 +/- 10.86 kg, % fat 13.78 +/- 4.31, fat free weight (FFW) 71.52 +/- 7.66 kg, pull-ups 9.03 +/- 4.79, push-ups 41.02 +/- 14.08, 1.5 mile run 737.60 +/- 108.11 s, sit and reach 32.00 +/- 8.5 cm, sit-ups 39.88 +/- 7.75, and total grip strength 116.75 +/- 17.67 kg. The physical performance assessment (PPA) consisted of the following: stair climb, hoist, forcible entry, hose advance, and victim rescue. Significant correlations (p < 0.01) were found between the PPA and the following: total grip strength (r = -0.54), FFW (r = -0.47), height (r = -0.40), pull-ups (r = -0.38), push-ups (r = -0.38), 1.5 mile run (r = 0.38), sit-ups (r = -0.32), weight (r = -0.30) and % fat (r = 0.30). Multiple regression analysis indicated that the best multiple predictor of PPA was the 1.5 mile run, FFW, and pull-ups, r = 0.73, p < 0.001. This investigation shows the importance of physical fitness as related to performance of fire suppression job tasks.

Voice problems and risk factors among aerobics instructors

Fifty female and four male aerobics instructors completed a questionnaire pertaining to vocal problems and variables that could indicate an increased risk for developing problems. The questions concerned teaching experience, physical data regarding instructional facilities, method of voice projection, music volume, history of illness, allergies, voice loss, hoarseness, smoking habits, and knowledge of vocal hygiene. The results showed that a significant number of instructors experienced partial or complete voice loss (44%) during and after instructing, as well as increased episodes of voice loss, hoarseness, and sore throat unrelated to illness since they began instructing. Significant variables associated with voice problems included sore throat and hoarseness following instruction, and shouting to cue the participants. It was also found that very few instructors in this study had any knowledge of vocal hygiene techniques.

Cardiovascular and metabolic costs of forward, backward, and lateral motion.

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 physiological effects of bench/step exercise

SummaryRecent investigation of acute cardiorespiratory responses to the current ‘popularised’ style of bench/step exercise has validated its use in improving aerobic physical fitness, particularly in women. However, no marked differences in relative measures of cardiorespiratory demand have been reported between men and women. Instructor data and training investigations further substantiate the effectiveness of bench/step exercise in promoting physical fitness, including upper body strength. However, the energy cost of bench/step exercise can vary dramatically. Important factors include, the selected step height, exercise rate, imposed step manoeuvre, routine format and use of hand-held weights. Hand-held weights may be more useful for men than woman.During training, bench/step exercise has been reported to yield a high incidence of grade I injury complaints, particularly in the calf and shoulder region. However, nearly 90% of these complaints were attributable to acute muscle soreness. Few serious injuries have been associated with the activity. Biomechanical research has shown that the ground reaction forces (GRF) experienced during bench stepping are lower than running and directly related to the step height and type of manoeuvre. In addition, compared with novices, instructors exhibit a moderation in the GRF pattern generated during landing. This suggests that a learning effect has occurred and that teachers yield a more consistent landing pattern. Finally, the activity may be effective in improving body composition, but a consideration of factors related to energy expenditure (e.g. exercise duration and dietary control) appear to be important in regimens prescribed for modifying body fat.

The physiological effects of aerobic dance. A review.

SummaryAerobic dance exercise is currently one of the most commonly practised adult fitness activities. The majority of the research pertaining to this form of exercise supports its application as a valid cardiovascular training alternative, especially for adult females if performed according to the American College of Sports Medicine (ACSM) guidelines. If however, the participant is interested in modifying body composition, training frequency, duration, or efforts toward caloric restriction may need to be increased or altered beyond those employed in the aerobic dance training investigations. The amount of energy expended during a bout of aerobic dance can vary dramatically according to the intensity of the exercise. ‘Low intensity’ dance exercise is usually characterised by less large muscle activity and/or less lower extremity impact, and music of slower tempo. Dance exercise representative of this variety requires a cost of approximately 4 to 5 kcal/minute. Several trials, however, have shown that vigorous ‘high intensity’ aerobic dance which entails using the large muscle groups can require 10 to 11 kcal/minute. The associated training outcomes could be affected by such differences in dance exercise intensity and style.

Vocal parameters of aerobic instructors with and without voice problems.

Aerobic instructors frequently experience vocal fatigue and are at risk for the development of vocal fold pathology. Six female aerobic instructors, three with self-reported voice problems and three without, served as subjects. Measures of vocal function (perturbation and EGG) were obtained before and after a 30-minute exercise session. Results showed that the group with self-reported voice problems had greater amounts of jitter, lower harmonic-to-noise ratios, and less periodicity in sustained vowels overall, but no significant differences in measures of perturbation and EGG were found before and immediately after instruction. Measures of vocal parameters showed that subjects with self-reported voice problems projected with relatively greater vocal intensity and phonated for a greater percentage of time across beginning, middle, and ending periods of aerobic instruction than subjects with no reported voice problems.

SELF-REPORTS ON THE EATING DISORDER INVENTORY BY FEMALE AEROBIC INSTRUCTORS

This study examined the possibility of earing disorders in 30 female aerobic dance instructors. All subjects completed a biographical questionnaire and the Eating Disorder Inventory. The results showed that the aerobic instructors yielded scores which were comparable to similarly aged female weight lifters but tended to be lower than those of women distance runners (also of similar age). Interestingly, 23% (n = 7) of the subjects reported a previous history of bulimia and 17% (n = 5) reported a previous history of anorexia. Thus, 40% of the instructors indicated a previous experience with eating disorders. Based on all 30 participants, the mean scores associated with Body Dissatisfaction, Drive for Thinness, Ineffectiveness, and Perfectionism were quite comparable to those previously established for anorexic groups. In addition, a relatively high percentage of the sample yielded scores which were actually greater than mean values associated with anorexia patients on nine of the 11 sub-scales. Based on these results, a number of the aerobic dance instructors possessed scores suggesting behaviors and attitudes consistent with female athletes whose sports emphasize leanness and comparable to those who have eating disorders.

Comparison of total and segmental body composition using DXA and multifrequency bioimpedance in collegiate female athletes.

Abstract Esco, MR, Snarr, RL, Leatherwood, MD, Chamberlain, NA, Redding, ML, Flatt, AA, Moon, JR, and Williford, HN. Comparison of total and segmental body composition using DXA and multifrequency bioimpedance in collegiate female athletes. J Strength Cond Res 29(4): 918–925, 2015—The purpose of this investigation was to determine the agreement between multifrequency bioelectrical impedance analysis (BIA) and dual-energy x-ray absorptiometry (DXA) for measuring body fat percentage (BF%), fat-free mass (FFM), and total body and segmental lean soft tissue (LST) in collegiate female athletes. Forty-five female athletes (age = 21.2 ± 2.0 years, height = 166.1 ± 7.1 cm, weight = 62.6 ± 9.9 kg) participated in this study. Variables measured through BIA and DXA were as follows: BF%, FFM, and LST of the arms (ARMSLST), the legs (LEGSLST), the trunk (TRUNKLST), and the total body (TOTALLST). Compared with the DXA, the InBody 720 provided significantly lower values for BF% (−3.3%, p < 0.001) and significantly higher values for FFM (2.1 kg, p < 0.001) with limits of agreement (1.96 SD of the mean difference) of ±5.6% for BF% and ±3.7 kg for FFM. No significant differences (p < 0.008) existed between the 2 devices (InBody 720—DXA) for ARMSLST (0.05 kg), TRUNKLST (0.14 kg), LEGSLST (−0.4 kg), and TOTALLST (−0.21 kg). The limits of agreement were ±0.79 kg for ARMSLST, ±2.62 kg for LEGSLST, ±3.18 kg for TRUNKLST, and ±4.23 kg for TOTALLST. This study found discrepancies in BF% and FFM between the 2 devices. However, the InBody 720 and DXA appeared to provide excellent agreement for measuring total body and segmental LST. Therefore, the InBody 720 may be a rapid noninvasive method to assess LST in female athletes when DXA is not available.