The Relationship Between Muscular Strength, Jump Power, and Bone Health in Collegiate Distance Runners.

Participation in sports, especially those involving impact loading, enhance bone mineral content (BMC) and density (BMD). Additionally, participation in impact loading sports may strengthen relationships between strength or power and bone variables. The purpose of this investigation was to examine relationships between measures of muscular performance and bone variables in Division I endurance athletes (29 males, 31 females, 19.6 ± 1.4 years). Dual-energy x-ray absorptiometry (DXA) scans were analyzed at the anterior-posterior (AP) and lateral (LAT) spine, femoral neck (FN), total hip (TH), whole body (WB), and ultra-distal forearm (UD) for BMC and BMD measures. WB scans provided information for bone-free lean mass (BFLM). Performance measures included absolute, and relative (to body weight), grip strength (GS) and absolute lower body power (LBP) derived from a vertical jump. Pearson correlation coefficients were determined between bone variables and muscular performance measures. Hierarchical multiple regression was used to quantify the variance explained in bone variables. Male runners showed strong relationships between absolute and relative GS and numerous bone variables. Female runner had significant relationships between absolute jump power and numerous bone variables. Sex, GS, and LBP explained 41-76% of BMC at the various bone sites and 12-30% of BMD. Results indicate that in collegiate men, greater strength is related to higher BMC and BMD, however this was not the case for women. In female collegiate distance runners, higher jump power was related to greater BMC and BMD.

A 2-Year Longitudinal Study of Bone Mineral Density in Collegiate Distance Runners.

ABSTRACT: Brimacomb, OE, Martinez, MP, McCormack, WP, and Almstedt, HC. A 2-year longitudinal study of bone mineral density in collegiate distance runners. J Strength Cond Res 37(8): 1654-1659, 2023-The purpose of this investigation was to examine changes in bone mineral density (BMD) of male and female collegiate distance runners over 2 years. Bone mineral density of 29 collegiate distance runners (16 men and 13 women) were measured 5 times over 24 months using dual-energy x-ray absorptiometry (DXA) at the anterior-posterior (AP) and lateral (LAT) spine, femoral neck (FN), total hip (TH), whole body (WB), and ultradistal (UD) forearm. Repeated-measures multivariate analysis of covariance, with bone-free lean mass (BFLM) as covariate, was used to compare mean BMD values. Adjusted for BFLM, there were no significant differences ( p > 0.05) in BMD at any site between sexes. There were no significant differences at the AP or LAT spine, FN, or WB between visit 1 and 5 for either sex. There was a significant increase in BMD ( p = 0.044) at the UD forearm over 2 years in males. However, 56% of the men ( n = 9) had a Z-score < -1.0 at the UD forearm. Seven of 11 women had Z-scores < -1.0 at the LAT spine and 4 of 13 had Z-scores < -1.0 at the AP spine. There were no significant changes in BMD at any site over the 2-year time frame, except a significant increase in BMD at the nondominant forearm in men. The spine appears to be an area of concern for women in this study when examining Z-score results. Coaches and medical staff need to continually educate collegiate endurance athletes about the importance of achieving and maintaining BMD through their college years.

Bone mineral density and hip structure changes over one-year in collegiate distance runners and non-athlete controls.

Modification of bone is continuous throughout life and influenced by many factors, including physical activity. This study investigated changes in areal bone mineral density (aBMD) and hip structure among male and female collegiate distance runners and non-athlete controls over 12 months. Using dual-energy x-ray absorptiometry (DXA) and hip structure analysis (HSA) software, aBMD at the posterior-anterior (PA) and lateral spine, femoral neck, total hip (TH), whole body (WB), and bone geometry at the narrow neck (NN) of the femur was measured three times over 12 months. HSA included cross-sectional area (CSA), cross-sectional moment of inertia (CSMI), and Z-section modulus (Z). Male runners had significantly higher aBMD at TH and WB and greater CSA, CSMI, and Z than male controls at the end of 12 months. Female controls had higher aBMD at the PA spine than female runners at the end of 12 months. Male runners had significant increases in aBMD at the PA (p = 0.003) and lateral spine (p = 0.002), and TH (p = 0.002), female runners had significant decreases in aBMD at TH (p = 0.015) and WB (p = 0.002), male controls had significant increases in aBMD at the PA spine (p < 0.001) and WB (p < 0.001), and female controls had significant decreases in aBMD at lateral spine and TH (p = 0.008) over the year. When applying covariates of bone-free lean mass and vitamin D, male distance runners demonstrated significant improvement in CSA (3.602 ± 0.139 vs. 3.675 ± 0.122 cm2, p = 0.05), CSMI (3.324 ± 0.200 to 3.467 ± 0.212 cm4, p < 0.05), and Z (1.81 ± 0.08 to 1.87 ± 0.08 cm3, p = 0.05) during the study. No other changes in hip structure occurred over the year. Distance running may be beneficial to aBMD and hip structure in college-age males but not females. Further research is needed on potential influences of weight-bearing activity, energy availability, and hormonal status on aBMD and hip structure in males and females.

Intensity of resistance training via self-reported history is critical in properly characterizing musculoskeletal health.

BACKGROUND: Intensity of resistance training history might be omitted or poorly ascertained in prescreening or data questionnaires involving musculoskeletal health. Failure to identify history of high-versus low-intensity training may overlook higher effect sizes with higher intensities and therefore diminish the precision of statistical analysis with resistance training as a covariate and bias the confirmation of baseline homogeneity for experimental group designation. The purpose was to determine the degree to which a single question assessing participant history of resistance training intensity predicted differences in musculoskeletal health. METHODS: In the first research aim, participants were separated into groups with a history (RT) and no history (NRT) of resistance training. The second research aim evaluated the history of resistance training intensity on muscular strength, lean mass, and bone mineral density (BMD), RT participants were reassigned into a low- (LIRT) or high-intensity resistance training group (HIRT). 83 males and 87 females (19.3 ± 0.6 yrs., 171.1 ± 9.9 cm, 67.1 ± 10.5 kg, 22.9 ± 2.8 BMI, 26.2 ± 7.2% body fat) completed handgrip dynamometry (HG) and dual-energy x-ray absorptiometry scans (DXA) for BMD and bone mineral-free lean mass (BFLM). RESULTS: A 3-group method (NRT, LIRT, HIRT) reduced type-I error compared with the 2-group method (NRT, RT) in characterizing the likely effects of one's history of resistance training. For the second aim, HIRT had significantly (p < 0.05) greater HG strength (76.2 ± 2.2 kg) and arm BFLM (6.10 ± 0.16 kg) than NRT (67.5 ± 1.3 kg; 4.96 ± 0.09 kg) and LIRT (69.7 ± 2.0 kg; 5.42 ± 0.14 kg) while also showing significantly lower muscle quality (HG/BFLM) than NRT (13.9 ± 0.2 vs. 12.9 ± 0.3). HIRT had greater BMD at all sites compared to NRT (whole body = 1.068 ± 0.008 vs. 1.120 ± 0.014; AP spine = 1.013 ± 0.011 vs. 1.059 ± 0.019; lateral spine = 0.785 ± 0.009 vs. 0.846 ± 0.016; femoral neck = 0.915 ± 0.013 vs. 0.970 ± 0.022; total hip = 1.016 ± 0.012 vs. 1.068 ± 0.021 g/cm2) while LIRT revealed no significant skeletal differences to NRT. CONCLUSIONS: Retrospective identification of high-intensity history of resistance training appears critical in characterizing musculoskeletal health and can be ascertained easily in as little as a single, standalone question. Both retrospective-questionnaire style investigations and pre-screening for potential participation in prospective research studies should include participant history of resistance training intensity.

Indicators of Sarcopenia: Sex Differences in Competitive Runners Prior to Peak Muscle Mass.

Strength, muscle mass, and muscle quality have been observed to be compromised in low body-mass index individuals such as competitive runners, increasing their risk for sarcopenia. The purpose was to compare indices of sarcopenia in young runners to age, height, body-mass, and body-mass index-matched non-runners. Handgrip strength and arm composition from dual-energy x-ray absorptiometry (baseline-T1, T2=5.3±1.4, T3=11.5±0.7 months later) were assessed in 40 non-runners and 40 runners (19.3±0.7 vs. 19.2±1.1 years, 170.7±10.3 vs. 171.1±9.1 cm, 60.2±7.4 vs. 60.2±7.9 kg, 20.6±0.9 vs. 20.5±1.5 kg m-2). The unitless variable of muscle quality, was defined as the sum of right and left maximal handgrip (in kg) divided by the sum of bone-free lean mass of both arms (in kg). Female runners displayed the highest muscle quality (T1=15.3±1.7; T3=15.7±2.0) compared to male runners (T1=13.7±1.4, p < 0.001; T3=14.2±1.6, p < 0.001) and male non-runners (T1=12.4±1.8, p=0.001; T3=13.2±1.6, p < 0.001), while female non-runners (T1=14.6±2.5, p=0.154; T3=15.1 ±2.2, p=0.124) showed higher muscle quality than male non-runners. Higher muscle quality in low-body-mass index females persists over one-year during young-adulthood and while running contributes to whole-body muscle mass accrual, it does not appear to be significantly associated with improvements in the most commonly used upper-body diagnostic indicator of sarcopenia.

Nutritional Intake and Energy Availability of Collegiate Distance Runners.

Objective: Research investigating the dietary habits of distance runners has presented varying results. Proper dietary intake appears to enhance distance running performance and low dietary intake may impact health. The purpose of this investigation was to perform a comprehensive evaluation of nutrient intake of collegiate distance runners with comparison to recommendations for athletes.Methods: Twenty-one men (Age: 19.6 ± 1.2 years; height: 177.1 ± 5.7 cm; body mass: 65.7 ± 4.6 kg; body fat: 15.5 ± 2.2%) and 20 women (Age: 20.2 ± 1.7 years; height: 162.9 ± 6.6 cm; body mass: 53.7 ± 6.5 kg; body fat: 23.3 ± 3.6%) volunteered to participate in the investigation. Energy intake was derived from the Block Food Frequency Questionnaire. Energy availability was calculated by subtracting exercising energy expenditure from daily energy intake, divided by bone free lean mass and fat-free mass. Macronutrient and micronutrient consumption were compared with the appropriate dietary reference intake values, U.S. Dietary Guidelines, or standards recommended for endurance athletes.Results: Dietary intake for the men was 2,741.0 ± 815.2kilocalories and for the women was 1,927.7 ± 638.2kilocalories. A majority of the runners (73%) consumed less than recommended levels of carbohydrates. All men and 75% of women met or exceeded the recommended daily protein intake. Fifty percent of women and 24% of men did not meet the recommended daily allowance for calcium. Ninety-five percent of the runners did not meet the RDA for vitamin D. All the men and 75% of the women met the RDA for iron intake, with 24 of the runners taking an iron supplement. Eight men and 10 women did not meet the recommended intake for potassium.Conclusion: The dietary intake in this group of distance runners is below that necessary for the level of energy expended in their training. Carbohydrate intake is below the recommended amount for endurance athletes, and the calcium and vitamin D intake may not be favorable for bone health in this group of distance runners.

Oral contraceptive use, bone mineral density, and bone turnover markers over 12 months in college-aged females.

INTRODUCTION: The purpose of this study was to compare bone mineral density (BMD) and bone turnover markers between combined oral contraceptive (COC) and non-COC users over 12 months. MATERIALS AND METHODS: COC users (n = 34, age = 19.2 ± 0.5) and non-COC users (n = 28, age = 19.3 ± 0.6) provided serum at baseline, 6 months, and 12 months. C-terminal telopepetides (CTX) and pro-collagen type 1 N-terminal propeptides (P1NP) were determined using ELISA. BMD was measured at the three time points using dual-energy x-ray absorptiometry (DXA). RESULTS: COC users had greater CTX than non-COC users at baseline (18.6 ± 8.2 vs. 13.8 ± 5.3 ng/mL, P = 0.021) and 6 months (20.4 ± 10.3 vs. 14.2 ± 8.5 ng/mL, P = 0.018). Controlling for lean mass, groups were similar in BMD. Over 12 months, non-COC users maintained BMD at the spine, while the COC users declined 2.2% in lateral spine BMD (0.773 ± 0.014 to 0.756 ± 0.014 g/cm2, P = 0.03) and 0.7% in anterior-posterior spine BMD (1.005 ± 0.015 to 0.998 ± 0.015 g/cm2, P = 0.069). Non-COC users increased in BMD of the whole body over 12 months (P < 0.001) while COC users had no change. Women who began COCs within 4 years after menarche had lower BMD at the hip and whole body. Women taking very low dose COCs (20 mcg ethinyl estradiol, EE) significantly declined in CTX, P1NP, and lateral spine BMD in comparison to participants using low dose COCs (30/35 mcg EE). CONCLUSION: College-aged women who did not use COCs increased BMD of the whole body, while COC users had elevated bone turnover, declines in spinal BMD, and lack of bone acquisition of the whole body over 12 months. Young females who initiate COC use early after menarche may experience skeletal detriments.

Bone mineral density, energy availability, and dietary restraint in collegiate cross-country runners and non-running controls.

PURPOSE: Weight-bearing activities such as running have been shown to be osteogenic. However, investigations have also shown that running may lead to site-specific deficiencies in bone mineral density (BMD) as well as overall low BMD. The purpose of this investigation was to evaluate and compare the BMD of female and male collegiate cross-country runners with non-running controls. In addition, energy availability and disordered eating attitudes and behaviors were assessed. METHODS: BMD of 60 collegiate cross-country runners and 47 BMI and age-matched non-running controls were measured via DXA scans. Participants completed a Block 2014 Food Frequency Questionnaire and Eating Disorder Examination Questionnaire. RESULTS: Controlling for fat-free mass (FFM), male runners showed greater BMD at the femoral neck (0.934 ± 0.029 vs. 0.866 ± 0.028 g cm2, p < 0.05), total hip (1.119 ± 0.023 vs. 1.038 ± 0.021 g cm2, p < 0.05), and whole body (1.119 ± 0.023 vs. 1.038 ± 0.021 g cm2, p < 0.05) than male controls. The female runners had greater whole-body BMD than female controls (1.143 ± 0.018 vs. 1.087 ± 0.022 g cm2, p < 0.05). Runners scored significantly higher than controls in dietary restraint (1.134 ± 1.24 vs. 0.451 ± 0.75, p < 0.05), male runners were significantly higher than male controls in eating concern (1.344 ± 1.08 vs. 0.113 ± 0.27, p < 0.05) and female runners were significantly higher than male runners in shape concern (1.056 ± 1.27 vs. 0.242 ± 0.31, p < 0.05). Forty-two percent of the male runners and 29% of female runners had an energy availability of less than 30 kcals kg-1FFM. CONCLUSION: It appears that distance running has beneficial effects on whole-body BMD and site-specific areas. Further research is warranted to further clarify the health effects of eating behaviors and EA of distance runners.

Heavy Episodic Drinking Is Associated With Poorer Bone Health in Adolescent and Young Adult Women.

OBJECTIVE: Osteoporosis is a costly bone disease characterized by low bone mineral density (BMD) that primarily affects postmenopausal women. One factor that may lead to osteoporosis is a failure to reach peak bone mass (PBM) in early adulthood. In older adults and animal models, heavy episodic drinking (HED) has been found to predict failure to reach PBM. However, this relationship has yet to be investigated in adolescent human females. METHOD: Female college students (N = 87; 60% White) reported age at menarche, hormonal contraceptive use, physical activity, smoking habits, and HED history via an online survey and then received a dual energy x-ray absorptiometry bone scan to assess both lean body mass and BMD at the lumbar spine. RESULTS: Frequent HED (having four or more drinks within 2 hours on 115 or more occasions since the start of high school, which is approximately equal to 1.6 episodes per month over this period) was associated with decreased vertebral BMD even when variables most commonly associated with bone health (lean body mass, physical activity, age at menarche, smoking, and oral contraception use) were controlled for. However, early HED initiation (beginning HED at age 15 years or younger) was not significantly related to BMD. CONCLUSIONS: This is the first study to assess the impacts of early HED initiation and frequent HED during adolescence on the bone health of young women. Results suggest frequency of HED before reaching PBM, but not age at initiation, may be negatively related to skeletal health during young adulthood. These findings encourage research into the association between HED and BMD in late adolescence.

Cardiometabolic Health Among Cancer Survivors: A 13-Week Pilot Study of a Combined Aerobic and Resistance Training Program.

PURPOSE/OBJECTIVES: To explore the feasibility of combined aerobic and resistance training (CART) as a safe method of improving cardiometabolic health among cancer survivors.
. DESIGN: Descriptive and longitudinal pilot study for exercise intervention.
. SETTING: University campus in Los Angeles, California.
. SAMPLE: A multiethnic population of cancer survivors (N = 11) was recruited by convenience sampling and physician referral. 
. METHODS: Consenting participants were prescribed CART for one hour per day, three days per week for 13 weeks.
. MAIN RESEARCH VARIABLES: Components of cardiometabolic health were measured, including resting heart rate (HRrest), blood pressure, body mass index, waist circumference, body fat percentage, and android fat percentage at baseline and after 13 weeks of training. Fasting blood glucose, insulin, adiponectin, leptin, tumor necrosis factor alpha, and C-reactive protein (CRP) also were assessed at baseline and after 13 weeks of training.
. FINDINGS: More than half of the participants reported living with at least two other chronic diseases or conditions in addition to a cancer diagnosis. Five of six African American and Hispanic participants reported the presence of at least two risk factors for metabolic syndrome, compared to one of five Caucasian participants. After 13 weeks of training, participants experienced an average decrease in waist circumference. Decrease in waist circumference was associated with a decrease in CRP. A relationship also was suggested between number of exercise sessions attended and improvement in HRrest. 
. CONCLUSIONS: A CART intervention among cancer survivors should continue to be explored in a larger sample to establish efficacy and effectiveness at improving cardiometabolic health. Because of the higher risk of comorbidity among cancer survivors in comparison to cancer-free adults, improving cardiometabolic health is as important as monitoring cancer recurrence. A need exists for increased attention to the post-treatment cardiometabolic health of cancer survivors and also for examining potential cardiometabolic health disparities among non-Caucasian cancer survivors.
. IMPLICATIONS FOR NURSING: CART may be a plausible alternative to reduce the risk of metabolic syndrome and improve cardiometabolic health among cancer survivors. Additional studies that continue to explore the efficacy and effectiveness of CART may provide more information to help nurses and physicians determine whether the cancer survivorship care plan should include an exercise-based alternative to intervene on cardiometabolic health.

Combined aerobic and resistance training improves bone health of female cancer survivors.

INTRODUCTION: Cancer pathogenesis and resulting treatment may lead to bone loss and poor skeletal health in survivorship. The purpose of this investigation was to evaluate the influence of 26 weeks of combined aerobic and resistance-training (CART) exercise on bone mineral density (BMD) in a multi-racial sample of female cancer survivors. METHODS: Twenty-six female cancer survivors volunteered to undergo CART for 1 h/day, 3 days/week, for 26 weeks. The Improving Physical Activity After Cancer Treatment (IMPAACT) Program involves supervised group exercise sessions including 20 min of cardiorespiratory training, 25 min of circuit-style resistance-training, and 15 min of abdominal exercises and stretching. BMD at the spine, hip, and whole body was assessed using dual-energy X-ray absorptiometry (DXA) before and after the intervention. Serum markers of bone metabolism (procollagen-type I N-terminal propeptide, P1NP, and C-terminal telopeptides, CTX) were measured at baseline, 13 weeks, and at study completion. RESULTS: Eighteen participants, with the average age of 63.0 ± 10.3 years, completed the program. Mean duration since completion of cancer treatment was 6.2 ± 10.6 years. Paired t-tests revealed significant improvements in BMD of the spine (0.971 ± 0.218 g/cm2 vs. 0.995 ± 0.218 g/cm2, p = 0.012), hip (0.860 ± 0.184 g/cm2 vs. 0.875 ± 0.191 g/cm2, p = 0.048), and whole body (1.002 ± 0.153 g/cm2 vs. 1.022 ± 0.159 g/cm2, p = 0.002). P1NP declined 22% at 13 weeks and 28% at 26 weeks in comparison to baseline (p < 0.01) while CTX showed a non-significant decrease of 8% and 18% respectively. CONCLUSIONS: We report significant improvements in BMD at the spine, hip, and whole body for female cancer survivors who completed 26 weeks of CART. This investigation demonstrates the possible effectiveness of CART at improving bone health and reducing risk of osteoporosis for women who have completed cancer treatment. The IMPAACT Program appears to be a safe and feasible way for women to improve health after cancer treatment.

Mind the gaps: missed opportunities to promote bone health among cancer survivors.

INTRODUCTION: Many cancer treatments have a negative effect on bone health and can lead to osteoporosis. Additionally, the risk of osteoporosis during cancer survivorship may differ by racial and ethnic group. Overall, cancer survivors may be poorly informed about the risk of bone loss due to treatment. EXERCISE PRESCRIPTION: Exercise can be prescribed to improve bone health and reduce risk of fracture. Women participating in the Improving Physical Activity After Cancer Treatment pilot study (IMPAACT) experienced significant improvements in bone health. The pilot work also suggests that cancer survivors of diverse racial/ethnic profiles may not fit the normal risk profile for osteoporosis and could be overlooked during screening. IN SUMMARY: The lack of awareness of poor bone health in cancer survivors needs to be addressed, especially for those who do not fit the normal osteoporosis risk profile. Exercise is a safe and effective part of a cancer survivorship plan and is useful in promoting bone health.

Physical activity in childhood may be the key to optimizing lifespan skeletal health.

Physical activities undertaken in childhood, particularly activities, which apply large forces quickly convey optimal benefits to bone mass, size, and structure. Evidence is accumulating that benefits persist well beyond activity cessation. This review examines the potential for early childhood activity to improve bone mineralization and structure and explores childhood activity as prevention for osteoporosis in later life.

Whole Body Vibration Training is Osteogenic at the Spine in College-Age Men and Women.

Osteoporosis is a chronic skeletal disease characterized by low bone mass which is currently challenging the American health care system. Maximizing peak bone mass early in life is a cost-effective method for preventing osteoporosis. Whole body vibration (WBV) is a novel exercise method with the potential to increase bone mass, therefore optimizing peak bone and decreasing the risk for osteoporotic fracture. The aim of this investigation was to evaluate changes in bone mineral density at the hip, spine, and whole body in college-age men and women who underwent a WBV training protocol. Active men (n=6) and women (n=4), ages 18-22 participated in the WBV training; while an additional 14 volunteers (1 male, 13 female) served as controls. All participants completed baseline and follow-up questionnaires to assess health history, physical activity, dietary intake, and menstrual history. The WBV training program, using a Vibraflex 550, incorporated squats, stiff-leg dead lifts, stationary lunges, push-up holds, bent-over rows, and jumps performed on the platform, and occurred 3 times a week, for 12 weeks. Dual energy x-ray absorptiometry (Hologic Explorer, Waltham, MA, USA) was used to assess bone mineral density (BMD, g/cm(2)). A two-tailed, t-test identified significantly different changes in BMD between the WBV and control groups at the lateral spine (average change of 0.022 vs. -0.015 g/cm(2)). The WBV group experienced a 2.7% and 1.0% increase in BMD in the lateral spine and posterior-anterior spine while the control group decreased 1.9% and 0.9%, respectively. Results indicate that 12 weeks of WBV training was osteogenic at the spine in college-age men and women.

The Effects of 24 weeks of Resistance Training with Simultaneous Elastic and Free Weight Loading on Muscular Performance of Novice Lifters.

The purpose of this investigation was to assess the effectiveness of variable resistance as provided through elastic plus free weight techniques in college aged males and females. Twenty novice lifters were randomly assigned to a traditional free weight only (6 males and 5 females) or elastic band plus free weight group (5 males and 5 females) and 9 more normally active controls (5 males and 4 females), were recruited to maintain normal activity for the duration of the study. No differences existed between control, free weight and elastic band at baseline for age, body height, body mass, body mass index, and body fat percentage. One-repetition maximums were performed for squat and bench press while both strength and power were assessed using isokinetic dynamometry. Elastic groups and free-weight groups completed 24 weeks of whole body, periodized, high intensity resistance (65-95% of one-repetition maximum) training three times/week. Training programs were identical except that the elastic group trained the barbell squat, bench press and stiff-legged deadlift with 20-35% of their total prescribed training loads coming from band resistance (assessed at the top of the range of motion) with the remainder from free weight resistance. A mixed-model analysis revealed that peak torque, average power and one-repetition maximums for squat were significantly greater after training for the elastic group compared to the control (p<0.05). In addition, the free weight group also showed significantly greater improvements over the control in peak torque and one-repetition maximums for squat and bench press. No significant differences were observed between the elastic band and free weight groups. Combined variable elastic band plus free weight exercises are effective at increasing strength and power similar to free-weights alone in novice college aged males and females. However, due to complexity in set-up and load assignment elastic adoption by novice lifters in an unsupervised situation is not advised.

Changes in bone mineral density in response to 24 weeks of resistance training in college-age men and women.

Osteoporosis is a chronic disease of major public health concern. Characterized by low bone mass and increasing risk for fracture, osteoporosis occurs to a greater extent in women. Resistance training is a mode of exercise that can be used to build peak bone mass during youth, thereby preventing osteoporosis later in life. Our aim was to evaluate the effectiveness of a resistance training protocol designed to apply loads to the hip and spine in men and women. We recruited recreationally active men (n = 12) and women (n = 12), ages of 18-23. An additional 10 participants (5 men, 5 women) served as controls. Volunteers completed questionnaires to assess health history, physical activity, dietary intake, and menstrual history. The training program was performed for 24 weeks, on 3 nonconsecutive days per week, including exercises for the upper, lower, and core musculature, marked by an undulating periodization varying between 67 and 95% of 1 repetition maximum (1RM) on the multijoint exercises of bench press, squats, and deadlifts. Dual energy X-ray absorptiometry (Hologic Explorer, Waltham, MA, USA) was used to assess bone mineral density (BMD, g · cm(-2)). A 2-tailed analysis of covariance, controlling for body mass index, revealed that in comparison to women, men had significantly greater increases in BMD at the lateral spine and femoral neck. Male exercisers were found to increase BMD by 2.7-7.7%, whereas percent change in women ranged from -0.8 to 1.5%, depending on the bone site. Both male and female controls demonstrated about 1% change at any bone site. Results indicate that 24 weeks of resistance training, including squat and deadlift exercises, is effective in increasing BMD in young healthy men. Similar benefits were not derived by women who followed the same protocol.

Elastic band prediction equations for combined free-weight and elastic band bench presses and squats.

Elastic bands added to traditional free-weight techniques have become a part of suggested training routines in recent years. Because of the variable loading patterns of elastic bands (i.e., greater stretch produces greater resistance), it is necessary to quantify the exact loading patterns of bands to identify the volume and intensity of training. The purpose of this study was to determine the length vs. tension properties of multiple sizes of a set of commonly used elastic bands to quantify the resistance that would be applied to free-weight plus elastic bench presses (BP) and squats (SQ). Five elastic bands of varying thickness were affixed to an overhead support beam. Dumbbells of varying weights were progressively added to the free end while the linear deformation was recorded with each subsequent weight increment. The resistance was plotted as a factor of linear deformation, and best-fit nonlinear logarithmic regression equations were then matched to the data. For both the BP and SQ loading conditions and all band thicknesses tested, R values were greater than 0.9623. These data suggest that differences in load exist as a result of the thickness of the elastic band, attachment technique, and type of exercise being performed. Facilities should adopt their own form of loading quantification to match their unique set of circumstances when acquiring, researching, and implementing elastic band and free-weight exercises into the training programs.

Validity of a dietary calcium questionnaire modified to include supplement use in athletes.

When conducting research in the area of bone health, accurate measurement of calcium intake is crucial. The rapid assessment method (RAM) is one technique that has frequently been used for its measurement of calcium intake. However, the RAM and other currently established questionnaires lack the assessment of dietary supplement use, which is common for athletes. Our objective was to evaluate the validity of a RAM questionnaire designed to assess daily calcium consumption which was further modified to meet the needs of athletes who frequently consume dietary supplements. Usefulness of the modified RAM for athletes and non-athletes was evaluated as well as utility among those who do and do not use supplements. The 47 volunteers (n = 31 women, 16 men) were between the ages of 18 and 25 including, 33 athletes and 14 controls. The population also contained 23 supplement users and 24 non-supplement users. Participants completed the modified RAM and were instructed to complete a three-day diet record (3DR), logging food intake for 2 weekdays and 1 weekend day. The data collected via the modified RAM was compared with the 3DR. Mean calcium intake was 935mg ± 420mg and 1085mg ± 573mg, for the modified RAM and 3DR respectively. A strong positive correlation (r) was found between calcium intake measured with the modified RAM and 3DRs (r(45) = 0.854, p < 0.01). Intraclass correlation coefficients (ICC) revealed that agreement between the two instruments was good (ICC = 0.76, df = 45, p < 0.01) and much improved when compared to agreements without consideration of supplements (ICC = 0.05, df = 21, p > 0.05). We have found the modified RAM to be a valid tool which can be used to estimate calcium intake in the athletes and controls we strive to study. The accuracy of this instrument improved by including assessment of dietary supplement sources of calcium. Key pointsWhen conducting research on bone health, accurate measurement of calcium intake is crucial. The rapid assessment method (RAM) is one technique that has frequently been used for its measurement; however, currently established questionnaires lack assessment of dietary supplement use, which is common for athletes.We report that estimated calcium intake from the LMU RAM modified to evaluate supplement use has good agreement with three-day diet records (3DRs). There was a strong correlation between the two methods with about 69% (r = 0.83, r(2) = 0.69) of the variability in calcium intake quantified via the LMU RAM being accounted for by the 3DR.Calculated intraclass correlation coefficients between 0.63 and 0.77 reveal that the LMU RAM appears to be a valid tool of measuring daily calcium intake in athletes and non-athletes and among those who do and do not use supplements.When evaluating calcium intake without considering supplements, agreement (ICC) and correlation (r) values decreased considerably.We found the LMU RAM to be a valid measurement of calcium intake in athletes and controls. Without the addition of a section on supplement use, estimated calcium intake would have decreased an average of 32%.