Newbury Victoria Kin 355 Discussion Section 4 Date submitted 9 12 13 Critical Analysis Attempt 1 Outline of Trends in Body Fat BMI and Physical Fitness Among Male and Female College Students Abstract Many previous publications on subject o Steps walked per day o Time spent on physical activities This study o used VO2max o 13 years Data o Body fat increasing 0 513 year males 654 year females o Indirect correlation VO2max body fat o Variance in VO2max 23 9 males 17 3 females o Supports physical fitness among college students declining body fat increasing Introduction Decline physical activity in college students o Important to healthy lifestyle Decreased risk of heart disease Obesity Cancer Psychological well being lower stress levels Better cognitive functioning o 50 population does no moderate vigorous physical activity o Decline from high school to college o Data from self reported height weight 35 of US college students and overweight obese Purpose of this study o Changes in levels of physical fitness Estimation of VO2max BMI Obesity body fat o 13 year 1996 2008 longitudinal study o Males vs females o Conducted at Andrews University Private with Emphasis on healthy lifestyle Materials and Methods 2 1 Participants o 5101 students o Each tested twice fall spring semester 2 2 MicroFit testing o FDA approved automated medical assessment tool Interactive skinfold caliper flexometer medical scale stationary bike chest strap transmitter heart rate receiving unit o Physical fitness measurements Body composition Weight Height Body fat Blood pressure Systolic Diastolic Muscular strength biceps Flexibility Resting heart rate Aerobic fitness Estimation of VO2max Total fitness score o Data about student Name Age Sex Date time students took tests 2 3 Body Composition o Major structural components of the body Muscles fat height cm weight kg o BMI body mass index Weight Height 2 o Skinfold test body fat millimeters Jackson Pollock method Males Chest abdomen thigh o Db 1 10938 0 0008267 MSF 0 0000016 MSF 2 0 0002574 age o Body fat 4 95 Db 4 5 x 100 Females Triceps surpailium thigh o Db 1 10994921 0 0009929 FSF 0 0000023 FSF 2 0 0001392 age o Body Fat 5 01 Db 4 57 x 100 2 4 Blood pressure bp resting heart rate rhr o Bp Oscillometric measurement method Done before active tests Biceps strength Aerobic fitness Subject sits upright relaxed feet on floor arm resting on table cuff around upper arm at heart level Systolic diastolic measurements mmHg o Rhr after Bp rhr 100 bpm Waits 5 mins Repeat Still Rhr 100 out of range for the Fitness Profile 2 5 Muscle Strength o Biceps strength test Maximum force single pull Static test Elbows fixed at 90 degrees No bar movement during pull Patients have no back arm injuries no reason that they shouldn t be lifting heavy objects Positioning back straight Rotate pelvis forward squeezing buttocks hold bar palms facing up strap adjusted elbow join at 90 degrees pull bar up 3 seconds biceps muscles only calculations in kg 2 6 Flexibility o Lower back and hamstring flexibility o Before test Participants sat on floor shoes off legs straight No participants had back injury reason they shouldn t try to touch your toes o During test participant reaches forward touches flexometer for 3 seconds recorded in cm 2 7 VO2max the maximum uptake of oxygen during a graded exercise o Astrand bike protocol used Recommended young middle age adults Starts with 3 min work stage Three additional 2 min work stages thereafter Heart rate below the Threshold Exercise Heart Rate TEHR Work load increased by 5 kp 25 watt or 1 0 kp 50 Watt Heart rate above TEHR Work level maintained for 3 mins Test complete afterwards TEHR ages below 50 120 bpm TEHR ages above 50 125 bmp o VO2max calculated using final work load and average of last two minute heart rates Formula VO2max mL kg min VO2max from table x 1000 weight kg x age factor 21 Age factor computation 100 1 37 x age 66 8 o Before test vigorous activities 15 mins per day on 3 day per week Positive answer initial load set at 2 0 kp 100 Watt Negative answer initial load 1 5 kp 75 Watt Females initial load constantly set at 1 0 kp 50 Watt heart monitors worn Computer responds to changing heart rate automatically adjusting work load level of bicycle ergometer 10 minutes test Two min cool down period Computer prints results compares results with national norms for age sex 2 8 Statistical analysis o Statistical Package for the social science used for data analysis o Linear regression used to measure trends VO2max BMI Body composition Year o Pearson correlations computed between VO2max BMI Body composition o P values or 0 05 on two sided tests statistically significant Results and discussion 3 1 Demographics o Population characteristics Subjects 45 male 55 female Mean body fat males 11 6 females 22 4 Mean VO2max males 38 7 mL kg min female 34 2 mL kg min BMI males 24 1 kg m 2 females 24 0 kg m 2 Other characteristics Age Bicep strength Flexibility Systolic BP Diastolic BP Resting heart rate Height Weight 3 2 Trends in fitness levels o Linear trend VO2max and years o Average decrease in VO2max per year males 812 mL kg min females 414 mL kg min o Noticeable increases 1998 1999 o Noticeable decreases 2000 2002 2007 o females recovery 2003 2006 o largest decline in VO2max males and females out of the 13 years 2007 o 2008 males improved females showed less improvement 3 3 Trends in BMI o Linear trend not significant for both sexes o Indirect correlation between student s VO2max levels and BMI Males 11 1 variance in the VO2max levels Females 17 1 variance in the VO2max levels 3 4 Trend in body fat o Problem with BMI don t know if person is overweight or heavily muscled o Body fat is more accurate measurement o Linear trend between body fat and years Males Body fat increase 0 513 year Females Body fat increase 0 654 year o Indirect correlation VO2max and body fat Males 23 9 variance Females 17 3 variance 3 5 Fitness categories o MicroFit criteria for age sex divided students by aerobic fitness VO2max results Poor Fair Fit Excellent o Decline in physical fitness different in males more pronounce and females Males 1999 dramatic increase 2007 increase peaked 2008 rebound Poor category increased disproportionally fewer males in excellent category Females Number in poor category fluctuates Several rebounds 2003 2006 2008 not as pronounced as males 2007 dramatic increase in poor category Poor category increased fewer losses from fair fit and excellent categories