Evaluation of the Bone Status in High-Level Cyclists

Abstract

The purpose of this study was to evaluate the bone status in highly trained professional cyclists subjected to regular training and tough competitions. Bone mineral density (BMD) was measured at different regions of interest by dual X-ray absorptiometry and main biological parameters related to bone metabolism were obtained in 29 cyclists. Lumbar BMD was 0.94±0.01 g/cm² (Z score=-1.28±0.07) and 1 cyclist out of 4 had and abnormally low value (Z-score <-2). The mean Z score at the total femoral site was-1.22±0.21 and 45% of athletes had a Z-score <-2. All femoral neck BMD values were within normal boundaries. The lowest BMD Z-score were measured at the mid radius or 1/3 proximal site with a mean Z-score of-1.77±0.78 but only 3 cyclists (15%) had Z-scores <-2. Biochemical parameters of bone formation, (serum ostéocalcine, and alkaline phosphatase) were normal. Three cyclists had low 25(OH) vitamin D levels. Blood testosterone and TSH were in the normal range. IGF-I levels were in the normal range; however, a significant inverse correlation was found with lumbar BMD (r=0.495; p=0.003). We confirm that cycling has no positive effect on BMD; BMD being often lower than in normal controls at the lumbar site; femoral BMD is less concerned. Absence of beneficial changes at the spine can be explained by biomechanical conditions related to the cyclists' position, reducing loading strains. It is necessary to pay greater attention to the bone status of high level athletes to prevent an increased risk of fractures.

Cycling and bone health: a systematic review

“…The lumbar spine has probably been the most studied region in this regard, with fairly conclusive results that lower BMD can be observed in cyclists compared with controls [29-35], practitioners of other sports [19,35-37] or reference values [4,38,39]. Moreover, the pelvic and hip regions, as key areas for osteoporotic fractures, and the whole body have been studied with concerning results.…”

“…Rector et al showed no differences between adult cyclists and runners in bone metabolism markers [37], and Guillaume et al reinforced that by showing these markers in normal ranges in a group of young cyclists [38]. However, Maïmoun et al [24] studied three groups of adult athletes (cyclists, triathletes and swimmers), compared to controls, and showed lower BAP in cyclists compared to any other group.…”

Direct effects of physical training on markers of bone metabolism and serum sclerostin concentrations in older adults with low bone mass

“…Previous studies have reported the short-term effects of different physical activities, including walking [ 37 , 38 ], outdoor jogging [ 39 ], aerobic exercise [ 28 , 40 , 41 ], resistance training [ 42 , 43 ] and cycling [ 27 , 44 , 45 ], on bone turnover. Gomes-Cabello et al summarized the effects of different training programs on bone turnover in a systematic review, and found that walking only modestly increased the loads on the skeleton above those caused by gravity; thus, this type of exercise does not effectively prevent osteoporosis in older adults.…”

Vitamin D and the Athlete: Current Perspectives and New Challenges

“…The stimulus of loading the musculoskeletal system through high-intensity dynamic sporting activity is proposed to compensate for 25[OH]D deficiency, with the absence of poor bone health in athletes [ 102 , 105 ]. However, non-weight-bearing athletes are prone to the same detrimental skeletal effects [ 104 , 106 ] and are at higher risk for low BMD when vitamin D status is low [ 107 – 109 ].…”