Skeletal Health and Associated Injury Risk in Collegiate Female Rowers

Height Restrictions for Dual-energy X-ray Absorptiometry: What Are Our Options for Body Composition and Bone Health Precision?

ABSTRACT

Redinger, AL, Russell, JL, Allen, SMF, and Baker, BS. Height restrictions for dual-energy X-ray absorptiometry: what are our options for body composition and bone health precision? J Strength Cond Res 38(7): e359-e365, 2024-Dual-energy X-ray absorptiometry (DXA) is commonly used for testing athlete's body composition, but many athletes are too tall. The first aim was to assess the viability of combining upper- and lower-body regions of interest (ROI), creating a combined scan for tall athletes who do not fit on the table and second, to provide practical solutions to DXA users who routinely scan tall athletes. Sixty subjects (34.8 ± 11.9 years; 171 ± 9 cm) completed 2 total-body DXA scans for baseline precision testing, using GE Lunar Prodigy (LP) or Hologic Horizon A (HA) models. Next, an upper body ROI from the skull to the distal femoral condyles was combined with a flipped scan (feet-to-head) ROI encompassing the proximal tibial plateau to the distal foot. Soft and bone tissue coefficient of variance (CV%) were calculated between the baseline scans and for the newly combined ROI scan. The combined ROI scan added 0.25-0.63% and 0.01-4.35% error rates for the LP and HA, respectively. An exploratory assessment of a GE Lunar iDXA demonstrated results similar to the HA with 4%+ error. The combined ROI scan is a user-friendly and precise method for older LP systems adding less than 1% error; however, newer DXA systems cannot use the stitched scan technique. Coaches and practitioners who use newer DXAs must prioritize consistently using the same boney landmarks (head, jaw, or feet) and ROI heights to provide precise longitudinal assessments of tall athletes' bone and body composition, until larger DXA tables become available.

Acute effects of muscle mechanical properties after 2000-m rowing in young male rowers

Background

The mechanical properties of muscles, such as changes in muscle tone and stiffness, are related to sports performance and injuries. Rowers are at increased risk of muscle fatigue and injury during high-repetition and heavy-load cyclic muscle actions. In view of this, the aim of the present study was to investigate the acute effect on muscle tone and stiffness, as well as bilateral muscle asymmetry, in high school rowers after a 2000-meter rowing ergometer test.

Methods

Twelve young male rowers (age = 17.1 ± 0.9 years, body weight = 73.5 ± 9.7 kg) were included in the study. The data of muscle tone (frequency) and stiffness of the posterior deltoids (PD), latissimus dorsi (LD), and rectus femoris (RF) (dominant and non-dominant side) before and after a 2000-m rowing ergometer test were collected using a handheld MyotonPRO device.

Results

After the rowing ergometer test, the muscle tone of dominant side PD, LD, and RF were significantly increased (p < 0.05). On the other hand, the muscle stiffness of the non-dominant side LD and RF, as well as the dominant side PD, LD, and RF were significantly increased after the rowing ergometer test (p < 0.05). The muscle tone and stiffness results showed that the dominant side PD, LD, and RF were all significantly higher than the non-dominant side after the rowing ergometer test (p < 0.05), where bilateral PD and RF exhibits moderate asymmetry (5% < symmetry index < 10%).

Conclusions

After a high-intensity and high-load 2000-m rowing ergometer test, PD, LD, and RF showed increases in muscle tone and stiffness, as well as changes in the symmetry of bilateral muscle mechanical properties.

Non-traditional HIIT-style ROTC training elicits positive bone quality and performance adaptations

Military personnel experience elevated bone injury incidence, partly due to arduous and repetitive training. Non-traditional High-Intensity Interval Training-style (HIIT) may benefit pre-enlisted Reserve Officer Training Corps (ROTC) cadet's musculoskeletal health and performance prior to military service. This study investigated 16 ROTC (n = 12 males; n = 4 females) and 15 physically active sex-, age-, and body mass-matched Controls' musculoskeletal health and performance from November to April. Total body, lumbar spine, and dual- hip dual-energy X-ray absorptiometry scans and 4%, 38%, 66% tibial peripheral quantitative computed tomography scans, blood draws (serum sclerostin and parathyroid hormone), and maximal muscle strength and aerobic capacity testing were completed. From November to April, ROTC improved bone density (DXA) of the dominant total hip and greater trochanter and non-dominant greater trochanter and 38% and 66% tibial total volumetric and cortical bone density (pQCT) similarly or more than Controls (all p ≤ 0.049). From November to April, ROTC also improved bench and leg press, and peak aerobic capacity (all p ≤ 0.013). From November to January, serum sclerostin increased (p ≤ 0.007) and remained elevated through April, while parathyroid hormone was unchanged. HIIT-style training induced positive musculoskeletal adaptations, suggesting it may be an excellent pre-service training modality for this injury prone group.

Oral Contraceptives and Female Rowers' Skeletal Health

ABSTRACT

Redinger, AL and Baker, BS. Oral contraceptives and female rowers' skeletal health. J Strength Cond Res 37(3): 669-677, 2023-Previous studies suggest that women using oral contraceptives (OC) experience fewer skeletal benefits from exercise compared with non-OC users. These findings may be especially important for athletes competing in weight-supported sports with a high prevalence of low bone mineral density and fracture, such as rowing. The purpose of this study was to examine skeletal health and bone injuries in collegiate female rowers. Forty-nine National Collegiate Athletic Association Division I female rowers completed general health, menstrual history, and bone physical activity questionnaire (BPAQ) surveys. Dual-energy X-ray absorptiometry (DXA) and peripheral quantitative computed tomography (pQCT) scans were used to assess bone content, density, and geometry. Contraceptive (OC users n = 14, non-OC users n = 35) and self-reported stress fracture (SFx n = 11, None n = 38) groups were analyzed using analysis of covariance and independent t -tests. Additionally, effect sizes ( d ) were calculated and significance was set at p ≤ 0.05. Oral contraceptive users had reduced lumbar spine areal bone mineral density after adjustment for Total BPAQ ( d = 0.58; p = 0.041) compared with non-OC users, but all other total body and site-specific DXA measures of bone mineral content and density were similar between contraceptive and injury groups. When comparing bone geometry of the 4, 38, and 66% tibiae using pQCT, no significant differences were found after adjustment for either contraceptive or injury group (all p > 0.060). Our findings suggest that OC usage was not associated with reduced skeletal health in competitive female rowers as evidenced by all Z-scores being above -2.0 and similar bone indices of mineralized content, density, geometry, and estimated strength between the groups.

DXA2: An Automated Program for Extraction of Dual-Energy X-Ray Absorptiometry Data

INTRODUCTION/BACKGROUND

Since the 1970s imaging devices have been rapidly advancing to provide researchers, clinicians, radiologists, and practitioners greater capabilities to image bone. Today, dual-energy X-ray absorptiometry (DXA) has emerged as the gold standard for the assessment of bone and body composition. Despite recent improvements in DXA image quality and reduced radiation dosages and scan times, the data extraction process has yet to be streamlined. The objective of this study was to design an application to allow DXA users to quickly and accurately transfer DXA report data directly into a user-friendly format.

METHODOLOGY

Initial development of the DXA Data Xtraction Assistant (DXA²) included processing 485 DXA reports from a previous study. Using Python script, numeric data from these DXA reports were converted to .csv files and then merged into one file, effectively compiling and organizing all table data from each report, by participant and visit number. A graphical user interface was then developed and beta tested using multiple DXA manufacturers, models, and software versions. To compare the effectiveness of the DXA² to the current standard of manual extraction, all 485 reports were manually transcribed into Microsoft Excel. The time required per report and the error rates were compared.

RESULTS

Manual transcription, by an experienced researcher, took over 10 h with an error rate of 0.6% and average error magnitude of 51%. Data extraction from DXA² took less than 25 min to retrospectively reformat all DXA reports for the DXA² and transcribe all 485 reports with 100% accuracy.

CONCLUSION

The DXA² application automates DXA report data extraction and aggregation for clinical, research, and applied settings and drastically reduces manual data entry time and eliminates transcription errors.

Bone, Biomarker, Body Composition, and Performance Responses to 8 Weeks of ROTC Training

CONTEXT

Military personnel engage in vigorous exercise, often resulting in higher bone mineral density; however, lower leg bone injuries are common in this population. Predictors of change in tibial bone quality and strength need to be characterized in this high-risk population.

OBJECTIVE

This study aimed to examine the effects of an eight-week military training intervention on total body and site-specific bone density and tibial bone quality, serum biomarkers (parathyroid hormone and sclerostin), body composition, and physical performance. Additionally, we sought to investigate what outcome variables (biomarkers, body composition, physical performance) would be predictive of estimated tibial bone strength in college-aged Reserve Officers' Training Corps (ROTC) members.

DESIGN

Prospective Cohort Study.

SETTING

XXX University. Patients of Other Participants: ROTC (n=14 male; n=4 female) were matched for sex, age, and body mass to physically active Controls (n=14 male; n=4 female). ROTC engaged in an eight-week training intervention, while physically active Controls made no changes to their exercise routines.

MAIN OUTCOME MEASURES

Pre general health questionnaires and pre, mid, and post intervention bone scans (DXA, pQCT), serum blood draws (parathyroid hormone and sclerostin), and physical performance measures (muscle strength and aerobic capacity) were tested.

RESULTS

ROTC participants exhibited significantly increased hip bone density and content (all p≤0.03) after the eight-week intervention. Sclerostin, not PTH, was a significant positive correlate and predictor in all ROTC models for estimated bone strength at the fracture prone 38% tibial site. Both groups decreased total body and regional fat mass and ROTC increased aerobic capacity (all p≤0.05).

CONCLUSIONS

All bone, body composition, and performance measures either improved or were maintained in response to ROTC training and sclerostin should be further investigated as a potential early indicator of changes in estimated tibial bone strength in military cohorts.