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 Students as Scientists 

 

SPOTLIGHT

  The “Make a Muscle” Study

Lynn, J.S., W.L. Stuhldreher, and K.R. Khalouf.

The purpose of this study was to investigate changes in body composition and muscular strength in novice bodybuilders in the pre-competition phase of training.

Fourteen competitors in an amateur bodybuilding competition (6 men, 8 women) were tested for body composition (underwater weighing, skinfolds, and circumferences) and strength (1RM bench and leg press) 12 weeks prior to and again 3-5 days prior to competition. Skinfold-corrected girths were calculated to assess changes in mid-arm muscle circumference (MAMC), and dietary macronutrient intake was examined using a 3-day diet record. During the 12 weeks there were reductions in body weight (-5.2 ± 3.6 kg in men; -2.5 ± 2.9 kg in women) and relative body fat (from 13.2 ± 3.4% to 9.4 ± 3.0% in men; from 17.9 ± 2.6% to 14.4 ± 1.3% in women). The MAMC declined in the men, but not in the women, suggesting that women were better able to maintain muscle mass.

In the combined sample, there was a significant correlation between the change in body weight and change in muscle circumference (r = 0.771, p ≤ 0.01). The men lost strength in both the upper and lower body as assessed by the bench press (-9.1 ± 5.9 kg) and the leg press (-29.5 ± 50.0 kg). Conversely, the women increased both upper and lower body strength (3.6 ± 4.5 kg and 15.9 ± 26.8 kg, respectively). Diets were hypocaloric and far exceeded recommendations for protein intake (51 ± 15% of energy for men and 56 ± 13% for women). Novice bodybuilders effectively lost fat, but not to the same extent as experienced competitors. Simple anthropometric measures may be useful in tracking body composition changes, and bodybuilders should seek professional advice on nutritional practices.

 

Impact of a 12 week pedometer-based walking program at Slippery Rock University

Jeramy Laird, Bethany Holes, Rachel Ondrejko, Kimberly Smith, Jeff Lynn, Joy Urda, Carena Winters

The purpose of this study was to determine the impact of a 12 week, pedometer-based walking program on physical activity levels, motivation for physical activity and barriers to physical activity. 

Methods: After signing an informed consent, participation waiver, and research questionnaire, 232 participants were provided a free pedometer and walking log. Participants were required to electronically submit their steps on a weekly basis and complete a post-questionnaire at the end of the 12 week program.

Results: Participants did not significantly increase their step counts from week 2 (49,472.95+35565 steps) to week 12 (52,286.50+39930 steps) (p=0.127), however, the 120 participants who completed the post-questionnaire self-reported the following outcomes (Table 1):
 

SELF-REPORTED OUTCOMES

Percentage

N

More motivation to continue physical activity

83%

n=99

More energy

64%

n=77

Higher self esteem

54%

n=65

More productivity at work/school

48%

n=57

Loss of Body Weight

35%

n=42

 Table 1. Self-reported outcomes of the 12 week walking program.

 

Participants also reported the following motivators and barriers to achieving physical activity during the program (Table 2):

 

MOTIVATORS

Percentage

N

 

BARRIERS

Percentage

N

Increase physical activity

76%

n=91

 

Lack of time

65%

n=78

Increase energy

55%

n=66

 

Bad weather

21%

n=25

Feel better about self

54%

n=65

 

Lack of energy

15%

n=18

Lose weight

42%

n=50

 

Lack of motivation

14%

n=17

Reduce stress

45%

n=54

 

Lack of priority

11%

n=13

Decrease health risks

33%

n=39

 

Lack of enjoyment

3%

n=4

  Table 2. Self-reported motivators and barriers to physical activity.

 

Conclusion: Although participants did not significantly increase their weekly steps, 95% of participants reported that they were more aware of their physical activity after participating in this program.  The results of this study will aid the investigators in addressing the perceived motivators and barriers to physical activity in future programs.

 

Comparison of Eight Abdominal Exercises using EMG, RPE, and Exercise Preference

Sarah Lillvik, Jenell Roberts, Sara Brett, Jared Patton, Joshua Henderson, Anne Hays, Kimberly Smith, and Jeff Lynn

To evaluate the effects of 8 different exercises on the myoelectric activity of the upper (URA) and lower rectus abdominis (LRA). Exercise preferences were also obtained.

Methods: Twenty-nine men (n=12) and women (n=17) aged 19.6±1.0y performed 8 randomly assigned abdominal muscle exercises: sit-up, crunch, Ab-Rocket, Bender Ball, Bean, Ab-Lounge, Ab-sling, and Stability Ball.  Each participant performed 1 exercise per day on 8 nonconsecutive days. Each exercise was performed for 60 repetitions or until failure at a cadence of 20 repetitions per minute. Surface electromyography (EMG) was recorded from the URA and LRA during each repetition. ANOVA with repeated measures compared EMG activity between exercises during the 10th repetition. Significance level was set at p ≤ 0.05. Participants also completed a questionnaire regarding their exercise preference and likelihood of equipment purchase.

Results: For the URA, the order of exercises from most to least EMG activity was; Ab-Sling, Ab-Rocket, crunch, sit-up, Stability ball, Bender Ball, Ab-Lounge, and Bean. The Ab-sling produced higher URA EMG activity than all other exercises (p<0.05). For the LRA, the order of exercises from most to least EMG activity was; Ab-Sling, sit-up, Ab-Rocket, crunch, Swiss Ball, Bender Ball, Ab-Lounge, and Bean. The Ab-Sling produced higher EMG activity than all the other exercises (p<0.05) except the sit-up. Survey data revealed that 74% of participants would neither use nor purchase the Ab-sling or Ab-Rocket. Conclusions: For the 8 exercises examined in this study, the Ab-Sling, Ab-Rocket, crunch, and sit-up produced the most muscle activation in URA and LRA, but because participants would neither purchase nor use the Ab-Sling or Ab-Rocket, the sit-up or crunch should be prescribed for rectus abdominis exercise.

 

Accuracy of three commercially available pedometers in measuring step count, distance traveled, and kilocalorie expenditure

Lauren Murberger, Ashley Sieczkowski, Jacob Secich, and Kimberly A. Smith

Objectives: To determine the accuracy of three commercially available pedometers, the BCF pedometer, Yamax Digi-Walker CW-701 pedometer, and Omron HJ-720 ITC pedometer, as a means to estimate step count, distance traveled, and kilocalorie (kcal) expenditure during a one mile treadmill walk.

Methods: Nineteen subjects aged 19.5+1.5y wore three pedometers on their waistband at the level of the umbilicus and in line with the middle of the thigh.  The Yamax and BCF pedometers were worn on the left hip and the Omron pedometer was worn on the right hip.  Subjects’ weight and stride length were entered in to each pedometer prior to walking one mile on a treadmill.  To determine the step count accuracy, the researchers counted each step using a tally counter. To determine the accuracy of distance traveled, the subjects walked exactly one mile on a calibrated treadmill. To determine the accuracy of kcal expenditure, subjects wore the Cosmed K4b2 portable metabolic analyzer which measures kcal expenditure.  An ANOVA with post-hoc analysis was used to determine differences between the actual and pedometer-estimated values for step count, distance traveled and kcal expenditure.  The significance level was set at p≤0.05.

 

Results: 

 

Steps

Distance (miles)

Kcals

Actual

2086.7+83.3

1.00+0.0

109.3+17.3

BCF

1869.4+259.7*

0.81+0.1*

51.0+7.0*

Yamax

2075.5+83.0

0.93+0.1

85.7+11.0*

Omron

2085.7+84.7

0.93+0.1

63.2+11.0*

  *Significant difference between actual and pedometer estimated values

There was no significant difference between actual steps taken and Yamax and Omron recorded steps (p>0.05), however, the BCF pedometer significantly underestimated step count (p<0.05).  There was no significant difference between actual distance traveled and Yamax and Omron recorded distance (p>0.05), however, the BCF pedometer significantly underestimated distance (p<0.05).  All three pedometers significantly underestimated kcal expenditure (p<0.05).

Conclusions: The Yamax and Omron pedometers can accurately measure step counts and distance, but none of the commercially available pedometers accurately estimated kcal expenditure.

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