| 1. |
- Vinther, Anders, et al.
(författare)
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Exercise-induced rib stress fractures: influence of reduced bone mineral density
- 2005
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Ingår i: Scandinavian Journal of Medicine & Science in Sports. - : Wiley. - 1600-0838 .- 0905-7188. ; 15:2, s. 95-99
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Tidskriftsartikel (refereegranskat)abstract
- Exercise-induced rib stress fractures have been reported frequently in elite rowers during the past decade. The etiology of rib stress fractures is unclear, but low bone mineral density (BMD) has been suggested to be a potential risk factor for stress fractures in weight-bearing bones. The present study investigated BMD in seven Danish national team rowers with previous rib stress fracture (RSF) and 7 controls (C) matched for gender, age, height, weight and training experience. Total body scan and specific scans of the lumbar spine (L2-L4), femoral neck and distal radius were performed using a DEXA scanner. The RSF subjects showed significantly lower L2-L4 BMD: RSF: 1.22 +/- 0.05 g cm(-2) (mean +/- SEM) (median 1.19 g cm(-2), range 1.02-1.37 g cm(-2)) compared to C: 140 +/- 0.04 g cm(-2) (median 1.41 g cm(-2), range 1.27-1.57 g cm(-2)) (P=0.028).The present results suggest that low bone mineral density may be a potential risk factor for the development of exercise-induced rib stress fractures in elite rowers.
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| 2. |
- Vinther, A, et al.
(författare)
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Exercise-induced rib stress fractures: potential risk factors related to thoracic muscle co-contraction and movement pattern
- 2006
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Ingår i: Scandinavian Journal of Medicine & Science in Sports. - : Wiley. - 1600-0838 .- 0905-7188. ; 16:3, s. 188-196
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Tidskriftsartikel (refereegranskat)abstract
- The etiology of exercise-induced rib stress fractures (RSFs) in elite rowers is unclear. The purpose of the study was to investigate thoracic muscle activity, movement patterns and muscle strength in elite rowers. Electromyographic (EMG) and 2-D video analysis were performed during ergometer rowing, and isokinetic muscle strength was measured in seven national team rowers with a history of RSF and seven matched controls (C). RSF displayed a higher velocity of the seat in the initial drive phase (RSF: 0.25 +/- 0.03, 0.25 (0.15-0.33) m/s vs C: 0.15 +/- 0.06, 0.18 (-0.11-0.29) m/s P = 0.028) (Mean +/- SEM, median and range). Further, RSF had greater co-contraction of m. serratus anterior and m. trapezius in the mid-drive phase (RSF: 47.5 +/- 3.4, 48.5 (35.8-60.2)% EMG signal overlap vs C: 30.8 +/- 6.5, 27.0 (11.2-61.6)% P = 0.043). In addition, the RSF subjects showed a lower knee-extension to elbow-flexion strength ratio (RSF: 4.2 +/- 0.22, 4.3 (3.5-5.1) vs C: 4.8 +/- 0.16, 5.0 (4.2-5.3) P = 0.043), indicating stronger arms relative to legs compared with controls. In conclusion, increased thoracic muscle co-contraction, altered movement patterns and reduced leg/arm strength ratio were observed in the RSF subjects, which may all predispose toward an increased risk of RSF.
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| 3. |
- Vinther, Anders, et al.
(författare)
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Testosterone and BMD in Elite Male Lightweight Rowers
- 2008
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Ingår i: International Journal of Sports Medicine. - : Georg Thieme Verlag KG. - 0172-4622 .- 1439-3964. ; 29:10, s. 803-807
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of the present study was to investigate if a relationship between BMD and testosterone levels could be identified in elite male lightweight rowers. Thirteen male lightweight national team rowers had their BMD measured in a DEXA scanner. Plasma concentrations of total testosterone (TT), free testosterone (IFT), dihydrotestosterone (DHT) and sex hormone binding globulin (SHBG) and additional parameters related to bone metabolism were measured. Plasma concentrations of TT, FT and DHT were in the lower part of the normal range, while BMD was close to or above normal. BMD of total body and L2-L4 were correlated to years of training (r(s): 0.59, p = 0.034 and r(s): 0.73, p = 0.005) and to TT (r(s): 0.56, p = 0.046 and rs: 0.63, p = 0.021). Moreover, L2 - L4 BMD was correlated to FT (r(s): 0.62, p = 0.024). After adjusting for years of training, partial correlation analysis showed a significant correlation between L2-L4 BMD and TT (r(s): 0.61, p < 0.05). BMD appears to be influenced by both testosterone levels and years of training in elite male lightweight rowers. The relatively high BMD and low testosterone levels indicate that the mechanical loading induced by rowing is more important to BMD than testosterone levels. Prospective investigations are needed to elucidate potential causal relationships.
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