Changes in Air Force Fitness Measurements Pre- and Post-Childbirth

Transcription

1 MILITARY MEDICINE, 177, 12:1519, 2012 Changes in Air Force Fitness Measurements Pre- and Post-Childbirth Lt Col Nicole H. Armitage, USAF NC*; Lt Col Denise A. Smart, WA ANG NC (Ret.) ABSTRACT U.S. Air Force (USAF) personnel are required to take periodic fitness assessments with minimum requirements to earn satisfactory performance evaluations. Active duty women are exempt from fitness testing during pregnancy and until 6 months postpartum. Although there is evidence that many women do not achieve prepregnancy fitness levels by 6 months postpartum, no published studies were found that evaluated changes in fitness measurements and assessment pass rates in active duty USAF women after childbirth. The purpose of this study was to compare USAF fitness assessment component measurements and overall pass rates at 6 months postpartum to prepregnancy measurements. A paired t-test analysis of fitness component measurements of 107 active duty women showed significantly larger abdominal circumferences, fewer push-up repetitions, and longer run times at 6 months postpartum when compared to prepregnancy assessments. No significant difference was found in sit-up measurements. Secondly, there was a significantly lower pass rate at 6-months postpartum compared to the prepregnancy time frame. Results from this study indicate that women may struggle to achieve prepregnant fitness levels and pass their fitness test by 6 months postpartum. More research is needed to discover which factors impact women s ability to successfully meet fitness standards postpartum. INTRODUCTION Active duty members of the U.S. Air Force (USAF) must be physically fit in order to accomplish their mission both at home station and while deployed overseas for military operations. The fitness level of USAF Airmen is assessed through a physical fitness test done annually or semiannually, depending on the score achieved on the previous test. 1 Although the USAF has had a fitness assessment for many years, it has recently undergone changes. In 2004, the primary means of assessing aerobic fitness changed from a cycle ergometry test to a 1½ mile run. At that time, abdominal circumference measurement, sit-up, and push-up components were also added to the overall fitness test. 2 As of July 1, 2010, a minimum passing score for each component requirement was added to the total passing score requirement. Currently, the USAF fitness assessment consists of four components: timed sit-up repetitions, timed push-up repetitions, abdominal circumference measurement, and a timed 1½ mile run. Points are assigned to each component measurement based on age and gender. In order to pass the test, Airmen need to achieve a minimum score in each component and an overall score of at least 75 out of Certain medical conditions can cause Airmen to be exempt from testing in one or all of the components of the fitness assessment. Pregnant women are exempt from testing until *Air Force Institute of Technology, Civilian Institute Programs, AFROTC Detachment 905, Washington State University, Pullman, WA st Medical Group, 12 South Grant Avenue, Fairchild AFB, WA The work reported herein was performed under United States Air Force Surgeon General approved Exempt Protocol Study No. FDG E. The views expressed in this material are those of the authors, and do not reflect the official policy or position of the U.S. Government, the Department of Defense, or the Department of the Air Force. doi: /MILMED-D the end of the calendar month that occurs 180 days after delivery unless they have developed another condition that exempts them from testing at that time. However, some women may have difficulty returning to a rigorous physical fitness regimen by 6 months postpartum, particularly if they were not able to maintain a fitness routine during pregnancy. This may be reflected in changes in fitness assessment measurements resulting in lower scores or even failure of the fitness assessment at 6 months postpartum. Failure of an Air Force fitness test may result in an unsatisfactory performance report and inhibit career progression. 1 As of January 2012, there were approximately 62,300 active duty women in the USAF, the majority who were of childbearing age. 3 Therefore, fitness performance is a potential concern for thousands of active duty Air Force women and for Air Force leadership. Maintaining physical fitness during pregnancy has been shown to have benefits for women throughout the perinatal period, including lower postpartum body mass indices 4 and decreased risk of gestational diabetes and pre-eclampsia. 5 Furthermore, the American College of Obstetrics and Gynecologists recommends continued exercise during pregnancy for most women. 6 However, many pregnant women will reduce their physical training or stop physical training altogether for various reasons resulting in a total loss of conditioning within several months. 7 Also, at some point in pregnancy, particularly the last trimester, task specific training such as sit-ups and push-ups become cumbersome and running may become difficult. In addition, physiologic changes in hormone levels affecting muscles and joints may increase risk of injury when performing specific exercises at a strenuous training level. 8 Lastly, complications such as preterm labor, pre-eclampsia, and placental problems that could occur during pregnancy may force women to stop exercising or even to be put on bed rest. MILITARY MEDICINE, Vol. 177, December

2 Studies have also shown that women who have regularly exercised before pregnancy have reported barriers to resuming exercise after having a baby. These barriers include soreness, fatigue, low tolerance to exercise, unpredictable schedules, organizational demands, household chores, lack of support from family and friends, lack of access to exercise facilities, and lack of information or encouragement from health care providers. 9 Participants in a study of Army Soldiers listed several factors that kept them from physical training in the postpartum period, including being overwhelmed while trying to balance work, child care issues and a new baby, certain medical conditions, and pain experienced from full breasts while running. 10 A literature review found no published studies that addressed the effects of childbirth on the ability of active duty USAF women to meet fitness standards at 6 months postpartum. In addition, data on pass rates for postpartum women specifically are not available. However, studies done on Army Soldiers showed that physical fitness scores generally decreased from prepregnancy to 6 months postpartum. 10,11 Furthermore, Soldiers were found to be more likely to fail a physical fitness test at 6 months postpartum than before becoming pregnant, and women perceived that 6 months after childbirth was not enough time to return to prepregnancy fitness levels. 10 Lastly, one study found that most postpartum failures of the Army Physical Fitness Test were a result of failing the run component. 11 Research in civilian populations indicates that fitness and strength levels during the postpartum period are below what they were before pregnancy. Treuth et al 12 looked at physical activity and compared aerobic and strength fitness levels before pregnancy with those at two postpartum time frames (6 and 27 weeks) for 63 women. Physical fitness was measured by a maximal VO 2 test on cycle ergometry and strength was measured by one-repetition maximum tests on leg press, leg extension, bench press, and latissimus pull-down machines. The authors found significantly lower maximal oxygen consumption, arm strength and leg strength at 6 and 27 weeks postpartum compared with the prepregnancy time frames. However, gains in strength were noted between 6 and 27 weeks postpartum indicating there was some, although not full, recovery to prepregnancy strength and fitness levels by 27 weeks postpartum. The above study is one of the few that addresses strength as well as cardiovascular fitness in perinatal women. However, it did not address the ability of women to do push-ups and sit-ups specifically after either a vaginal or cesarean delivery. One study was found that examined inter-recti distance and abdominal muscle function as measured by trunk flexion tests, including curl-ups, after childbirth. 13 The researchers of this study noted only slight decreases in interrecti distances but some improvement in muscle function between 7 weeks and 6 months postpartum. However, interrecti distances and abdominal muscle function were still significantly less than nulliparous matched controls at 6 months postpartum. None of the women in the control group or experimental group in this study engaged in physical training to improve muscle function. This suggests that abdominal muscle function does not naturally return to prepregnancy levels by 6 months postpartum. These studies indicate that active duty women not only may have difficulty returning to optimal fitness levels by 6 months postpartum but also may have more difficulty meeting minimum fitness standards. Failure to achieve fitness standards not only may contribute to feelings of being overwhelmed and stressed on the part of the individual, but also can result in more time away from the duty section in order to do additional training in an effort to pass the assessment on a mandatory retest. Air Force Instruction states that USAF members who fail to comply with fitness standards may be subject to adverse employment actions. However, no studies were found that indicated changes in separation or promotion rates in childbearing women because of fitness assessment failures. It is unclear whether it is from decreased physical training or physiologic changes that occur during pregnancy (or both), but there is evidence in civilian and military studies that women do not generally achieve prepregnancy fitness levels by 6 months postpartum. An examination of the literature did not reveal any studies that addressed the impact of childbirth on fitness measurements for active duty Air Force women. The purpose of this study is to determine if there are changes in measurements from all components of the Air Force fitness test as well as pass rates between prepregnancy tests and those taken after childbirth. The first aim of this study is to compare first postpartum fitness test component measurements and related metric data of active duty Air Force women with the measurements from their last test before pregnancy. The second aim is to compare overall fitness assessment pass rates before pregnancy with overall pass rates at 6 months postpartum. METHODS This study was conducted at two different Air Force bases on the west coast of the United States. The bases were chosen because of proximity to the researchers, and they both were guided by the same Air Force Institutional Review Board. Approval was obtained from the appropriate Air Force Institutional Review Board reviewer before commencing the study. Fitness data and available demographic data on active duty women who had a documented duty limiting condition for pregnancy were obtained retrospectively from existing databases at both bases. Inclusion criteria were as follows: women had to be active duty members of the Air Force with a recorded fitness assessment before a pregnancy and around 6 months postpartum, and both assessments had to be done within a 2-year time frame. Exclusion criteria consisted of women with pregnancies that lasted less than 20 weeks gestation and women with recorded assessments greater than 2 years between the two time frames MILITARY MEDICINE, Vol. 177, December 2012

3 A power analysis done before the study indicated that a sample size of at least 64 would be needed for a paired t-test analysis of component measurements and a sample size of at least 87 would be needed for a c 2 analysis of pass rates in order to achieve 0.80 power with estimated medium effect size. Based on initial reports on numbers of active duty women with a duty limiting condition for pregnancy generated from the existing databases, it was thought that an adequate sample size could be obtained from the two bases combined. All data that was available from the data bases from participants who met criteria between January 1, 2008 and October 31, 2011 were recorded into an IBM SPSS Statistics 19 database. No personally identifiable information was recorded in the database. Only minimal demographic data were available to be recorded and was limited to age and rank. Data from the four components of the fitness assessment and two time frames (prepregnancy and postpartum), including actual measurements, scores, and whether or not the participant passed the assessment, were recorded. IBM SPSS Statistics 19 software was used for all the data analysis in this study. A paired t-test analysis was done to compare each of the four component measurements between the two time frames. Total fitness assessment scores were not compared between the two time frames because the majority of the participants tested with different scoring criteria between the two time frames. This occurred because the USAF changed the scoring system on July 1, A c 2 analysis was used to compare pass rates between the two time frames, between the two rank categories (officers and enlisted), and between the two bases. Descriptive frequency analyses were used to obtain demographic information and the frequency of specific component failures. RESULTS Data were obtained from a total of 107 active duty women from two Air Force bases. The mean age was 27.8 years (range years) at the time the postpartum fitness assessment was taken. Table I contains the summary of numbers of participants in each age category, base, and rank (officer or enlisted). All of the participants had a recorded abdominal TABLE I. Demographics of Study Population Variable Total Number of Participants (N = 107) Percentage (%) Age Range Under Rank Enlisted Officer Base TABLE II. Paired Fitness Component Statistics Component Mean Total Participants SD Abdominal Circumference Prepregnancy 29.4 inches Postpartum 30.2 inches Run Time Prepregnancy seconds Postpartum seconds Sit-Ups Prepregnancy 41.4 repetitions Postpartum 40.0 repetitions Push-Ups Prepregnancy 31.3 repetitions Postpartum 25.0 repetitions circumference for both time frames. However, recorded values were not available from participants who were exempt from specific components of the fitness assessment at one time frame or another. Therefore, the paired t-test analysis was performed for each of the other three components only on participants who had recorded measurements for both time frames (Table II). Reasons for exemptions from certain components were not available from the database for analysis. Results from the paired t-test analysis showed significant differences for the abdominal circumference, 1½-mile run, and push-ups component measurements between the prepregnancy and postpartum time frames (Table III). However, no significant difference was found in sit-up repetitions between the two time frames. The mean abdominal circumference (N = 107) increased from (SD = 2.71) inches before pregnancy to (SD = 3.52) inches postpartum (t = 3.47, degrees of freedom (df) = 106, p = 0.001). The mean run time (N = 85) increased from (SD = 99.12) seconds before pregnancy to (SD = ) seconds postpartum (t = 3.42, df = 84, p = 0.001). The mean number of sit-ups (N = 88) decreased from (SD = 9.72) repetitions before pregnancy to (SD = 10.73) repetitions postpartum (t = 1.32, df = 87, p = 0.190). The mean number of push-ups (N = 84) decreased from (SD = 12.41) before pregnancy to (SD = 10.74) postpartum (t = 4.27, df = 83, p < 0.001). The data were further analyzed to determine if there were still differences in women who completed all components TABLE III. Paired t-test Analysis of Individual Component Differences Component Mean Difference t Value Significance Abdominal 0.79 (inches) * Circumference Run Time (seconds) * Sit-Ups 1.48 (repetitions) Push-Ups 6.29 (repetitions) 4.27 <0.001* *Indicates significant difference. MILITARY MEDICINE, Vol. 177, December

4 TABLE IV. c 2 Analysis of Pass Rates Between Prepregnancy and Postpartum Time Frame Total Not Passing Percentage (%) c 2 Significance Prepregnancy 6* Postpartum 27* 26.5 *Total N = 102 of the fitness test during both time frames. Only 70 of the 107 women completed all four components of the fitness assessment during both time frames. Analysis using the paired t-test on only these 70 women indicated similar results to the results from the full population with significant differences noted in the abdominal circumference, run, and push-up components but no significant difference in the sit-up component. This study also noted that only 73 women (68%) performed all components of the fitness assessment during the postpartum time frame compared to 98 women (92%) who completed all components before pregnancy. The difference in pass rates between the two time frames was analyzed using a c 2 analysis (Table IV). This analysis showed that of the 102 women who had a prepregnancy fitness assessment and a postpartum fitness assessment pass/fail determination recorded; 6 did not pass the prepregnancy time frame and 27 did not pass during the postpartum time frame. The difference between pass rates at the two time frames was statistically significant at the 0.05 level (c 2 = 10.75, df = 1, p = 0.001). Of the 27 women who did not pass the test during the postpartum time frame, 2 were officers (N = 17) and 25 were enlisted (N = 85). There were not significant differences in pass rates between officers and enlisted (c 2 = 2.27, df = 1, p = 0.132) or between Base 1 and Base 2 (c 2 = 0.14, df = 1, p = 0.711). The scoring system for the USAF fitness assessment changed on July 1, 2010 to include minimum passing scores for each component in addition to a total passing score. Of the 102 women, the majority (N = 88) had a prepregnancy assessment using the old scoring system and a postpartum assessment using the new scoring system. A further analysis was done on the individual component pass rates from the 26 women who failed the postpartum fitness assessment based on the new standard with minimum component requirements. For the abdominal circumference component, 30.8% (N = 8) failed, 45% (N = 9) failed the run component, 65.2% (N = 15) failed the sit-up component, and 50% (N = 11) failed the push-up component. A comparison was made in postpartum pass rates between women who completed all components of the fitness assessment (N = 73) and those who did not (N = 33), and no significant difference in pass rates was found (c 2 = 0.458, df = 1, p = 0.499). DISCUSSION There was a significant difference in average measurements from the prepregnancy to postpartum time frames for the abdominal circumference, run, and push-up components of the fitness assessment. Although the differences in these components appear to be small, they are also clinically significant in that many women may find it difficult to quickly decrease their run times by 30 seconds, decrease their abdominal circumference by 1 inch, or increase their push-up repetitions by 6 if they are already putting forth maximal effort. However, there was not a significant difference in average measurements between the prepregnancy and postpartum time frames for the sit-up component. These results suggest that active duty women, on average, do not attain prepregnancy fitness levels by 6 months postpartum as measured by the Air Force fitness assessment with the exception of sit-ups. It is unclear why the participants in this study were able to achieve prepregnancy levels for sit-ups but not for abdominal circumference, run times, or push-ups. It is surprising that the sit-up component was the one component that did not show a statistical difference between the two time frames because of the physiological changes that occur during pregnancy and delivery that affect the abdominal muscles and women s ability to train for sit-ups. Interestingly, of the women who failed the fitness assessment during the postpartum period, a higher percentage failed the sit-up component than failed any other component. The fitness assessment failure rate of 26.5% during the postpartum time frame was quite a bit higher than the approximately 6% failure rate before pregnancy. It is difficult to know if this is a result of the difference in component measurements or because of the change in fitness assessment requirements that occurred on July 1, Fontaine 14 reported an overall USAF fitness assessment pass rate of 80.8% in November This equates to an overall failure rate of 19.2%, which is more consistent with the 26.5% failure rate found in this study. The limitations of this study are that data from only two Air Force bases were obtained and only from active duty Air Force members. Results might not be generalized to other bases or members of other branches of the military. In addition, in most of the participants, the scoring system for the fitness assessment changed between the prepregnancy and postpartum time frames. It is unknown what affect this may have had on performance. Results from this study emphasize the need to further explore active duty women s physiologic changes during and after childbirth. Not only must women recover from the birth process, adjust to the maternal role, experience sleep fragmentation related to newborn sleep patterns and feeding needs, and prepare for return to work in 4 to 6 weeks, they must also begin to plan and prepare for their next physical fitness test at a time when they are preoccupied with maternal roles. Complications of childbirth and postpartum complications such as breast problems, pain at incision site, and urinary problems may also impact recovery. 15 Women who plan to breastfeed longer than 4 to 6 weeks have additional physiologic and logistical needs MILITARY MEDICINE, Vol. 177, December 2012

5 Resources that target postpartum women need to be developed with the understanding that household and newborn demands place additional strain on the new mother and family. Policies supporting extensions for fitness testing need to be considered given that each aspect of the fitness test is muscle and skill specific. In other words, if a woman has not been able to maintain push-ups, sit-ups, and running during the pregnancy because of medical limitations, then a reasonable expectation is to extend the testing period to 9 to 12 months. Military facilities need to have fitness trainers and certified programs that meet the postpartum woman s needs to encourage a safe and reasonable return to prepregnancy fitness baselines. CONCLUSION This study shows that fitness assessment performance tends to be lower at the 6-month postpartum time frame when compared to prepregnancy performance. This could be especially problematic for active duty women who are borderline in passing their fitness test before pregnancy. This information could be useful for clinicians who care for childbearing active duty women and provide anticipatory guidance to these women. This information could also be useful for commanders and supervisors in advising perinatal women about fitness. There is much that is still unknown about achieving fitness standards after childbirth. More research is needed to assess a larger population of women and to see if these findings can be replicated in other populations. Second, it would be helpful to compare physical assessment scores in both time frames from the same scoring system. In addition, further research to determine the relationship between fitness scores and other variables such as participating in a fitness program, parity, type of delivery, and type of infant feeding would help to understand which factors affect fitness after childbirth. Lastly, qualitative research is needed to discern what types of challenges postpartum women may encounter in trying to achieve prepregnancy fitness levels. This information could then be used by military clinicians to plan interventions aimed at assisting perinatal women attain optimal fitness levels. REFERENCES 1. United States Air Force: Air Force Instruction , Fitness Program Available at accessed September 22, United States Air Force: Air Force Instruction , The Air Force Fitness Program Available at accessed January 25, Air Force Personnel Center: Demographics Report January Available at accessed February 18, Downs DS, Hausenblas HA: Pregnant women s third trimester exercise behaviors, body mass index, and pregnancy outcomes. Psychol Health 2007; 22(5): Gavard JA, Artal R: Effect of exercise on pregnancy outcome. Clin Obstet Gynecol 2008; 51(2): American College of Obstetricians and Gynecologists: Exercise during pregnancy and the postpartum period. Clin Obstet Gynecol 2002; 46: Melzer K, Schultz Y, Boulvain M, Kayser B: Physical activity and pregnancy: cardiovascular adaptations, recommendations and pregnancy outcomes. Sports Med 2010; 40: Artal R, O Toole M: Guidelines of the American College of Obstetricians and Gynecologists for exercise during the pregnancy and postpartum period. Br J Sports Med 2003; 37: Jenkins C, Handcock P, Burrows L, Hodge K: Exercise barriers faced by first-time mothers. NZCOM J 2006; 35: Weina SU: Effects of pregnancy on the Army Physical Fitness Test. Mil Med 2006; 171(6): Lombardi W, Wilson S, Peniston JB: Wellness intervention with pregnant soldiers. Mil Med 1999; 164(1): Treuth MS, Butte NF, Puyau M: Pregnancy-related changes in physical activity, fitness, and strength. Med Sci in Sports Exerc 2005; 37(5): Liaw L, Hsu MJ, Liao CF, Liu MF, Hsu AT: The relationships between inter-recti distance measured by ultrasound imaging and abdominal muscle function in postpartum women: a 6-month follow-up study. J Orthop Sports Phys Ther 2011; 41(6): Fontaine S: 4 in 5 Airmen passing PT test, Air Force says. Air Force Times, Available at air-force-4-in-5-airmen-passing-pt-test ; accessed June13, Declercq ER, Sakala C, Corry MP, Applebaum S: Listening to mothers II: report of the second national U.S. survey of women s childbearing experiences. J Perinat Educ 2007; 16(4): Sleutel M: Breastfeeding during military deployment: a soldier s story. Nurs Womens Health 2012; 16(1): MILITARY MEDICINE, Vol. 177, December