|Year : 2017 | Volume
| Issue : 1 | Page : 27-31
The effect of running on femoral bone mineral density
Tarek Saad Shafshak1, Mohamed Mustafa Rezk2, Sarah Sayed El-Tawab1, Marwa Mokhtar Mohareb1
1 Department of Physical Medicine, Rheumatology and Rehabilitation, Faculty of Medicine, Alexandria University, Al-Azaritah, Alexandria, Egypt
2 Department of Clinical and Chemical Pathology, Faculty of Medicine, Alexandria University, Al-Azaritah, Alexandria, Egypt
|Date of Web Publication||3-Jan-2017|
Sarah Sayed El-Tawab
Department of Physical Medicine, Rheumatology and Rehabilitation, Faculty of Medicine, Alexandria University, Medaan El Khartoom Square, Al-Azaritah, Alexandria
Background: Mechanical loading plays an essential role in the bone remodeling regulation. Running is a medium impact aerobic activity, which has been previously reported as exerting both positive and negative impacts on skeletal health. Aim: To study the effect of running on femoral bone mineral density (BMD), testosterone, and osteocalcin level among young male runners. Subjects and Methods: The study was carried out on 20 male runners aged between 18 and 25 years. Twenty healthy age-matched sedentary men were enrolled as a control group. BMD at the femoral neck, Ward's triangle, greater trochanter, and total femur was measured by dual-energy X-ray absorptiometry in all participants. The Z-score was selected for BMD assessment. Serum calcium, phosphorous, testosterone, and osteocalcin level were measured. Results: Runners had significantly higher BMD at all sites (P < 0.01). Runners had a higher serum osteocalcin (15.729 ± 13.722 vs. 4.980 ± 1.3724 ng/ml, P = 0.002) and lower serum testosterone level (3.844 ± 1.617 vs. 5.994 ± 2.190 ng/ml, P = 0.001). Serum level of osteocalcin and the duration of running were correlated positively with BMD among runners. Conclusion: This study confirms the positive osteogenic effect of running on BMD.
اثر الجري على الكتافة المعدنية لعظم الفخذ
خلفية البحث: يؤدي العبء الميكانيكي دوراً اساسياً في تنظيم إعادة تشكيل العظم. علما بان الجري هو نشاط هوائي متوسط الاثر لديه آثار ايجابية وسلبية على الصحة الهيكلية.
الهدف: هو دراسة أثر الجري على الكثافة المعدنية لعظم الفخذ (BMD) , التستستيرون, ومعدل الاوستيوكالسن في العدائين الرجال.
المواد والوسائل: تم إجراء الدراسة على عشرين عداءً من الرجال تراوحت أعمارهم بين 18-25 عاماً. وتم إدراج عشرين رجلاً سليماً من محبي الجلوس كعينة ضابطة. تم قياس كثافة العظم المعدنية في عنق الفخذ, و مثلث وارد, والعظم المدور الاكبر, وكامل الفخذ بواسطة الأشعة السينية الامتصاصية الثنائية لكل المشاركين. واختير مقياس Z لتقييم الكثافة المعدنية للعظم. بالإضافة الى قياس معدل الكالسيوم، الفسفور، التستوستيرون والاوستيوكالسين بمصل الدم.
النتائج: كانت الكثافة المعدنية للعظم أعلى بشكل بارز لدى العدائين في جميع المواقع (P<0.01). وكانت نسبة الاوستيوكالسين بالدم أعلى لدى العدائين (15.729±13.722 مقابل ng/ml 1.3724 ±4.980 _، P=0.002) ومعدل تستوستيرون أقل (1.617 3.844+_ مقابل 2.190 ng/ml، P=0.001 (5.994+. معدل الاوستيوكلسيتونين بالدم يرتبط إيجابياً مع الكثافة المعدنية للعظم لدى العدائين.
الخلاصة: أوضحت هذه الدراسة أثر الجري على البناء الإيجابي للكثافة المعدنية للعظم.
Keywords: Bone mineral density, dual-energy X-ray absorptiometry and osteocalcin, running
|How to cite this article:|
Shafshak TS, Rezk MM, El-Tawab SS, Mohareb MM. The effect of running on femoral bone mineral density. Saudi J Sports Med 2017;17:27-31
|How to cite this URL:|
Shafshak TS, Rezk MM, El-Tawab SS, Mohareb MM. The effect of running on femoral bone mineral density. Saudi J Sports Med [serial online] 2017 [cited 2017 Oct 23];17:27-31. Available from: http://www.sjosm.org/text.asp?2017/17/1/27/197466
| Introduction|| |
Bone remodeling is a continuous process in which bone is removed by osteoclasts and replaced with newly synthesized bone by osteoblasts. It occurs to preserve the mechanical integrity of the skeleton and regulate calcium homeostasis. The mechanical environment plays an essential role in the bone remodeling regulation. Hormonal, local, nutritional, and genetic factors are also implicated in the process of bone remodeling. It is now accepted by many researchers that osteoporosis is a pediatric disease, with 60% of its risk can be explained by the amount of bone mass achieved by early adulthood, hence maximizing the bone mass during this period of life is an important goal in the prevention of osteoporosis.
Running is a medium impact aerobic activity, which provides some site-specific enhancement of bone mineral density (BMD) over nonathletic control. Running has been previously reported as exerting both positive and negative impacts on skeletal health. The positive impact of running on bone was concluded by previously published researches., In contrast to that other studies described low BMD values in runners., Exercise induces changes in many hormones that affect bone including growth hormone, testosterone hormone, cortisol level, follicular-stimulating hormone, and luteinizing hormone (LH). Different variables can influence the magnitude of these changes. These include intensity, nature, and duration of the exercise, physical fitness, age, and body composition. Although many techniques are available for BMD measurement, central dual-energy X-ray absorptiometry (DEXA) of the hip (femoral neck) remains the gold standard for diagnosing osteopenia or osteoporosis. However, monitoring the acute changes in bone is difficult with the static information provided by the BMD measurement. Consequently, the popularity of biochemical bone turnover markers has grown to measure early bone turnover changes. Markers of bone formation include the alkaline phosphatase, osteocalcin, and procollagen Type I C-terminal propeptide and markers of bone resorption are hydroxyproline and tartrate-resistant phosphatase acid. The current study was conducted to study the effect of running on femoral BMD, testosterone, and osteocalcin levels among young male runners.
| Subjects and Methods|| |
The study was carried out on twenty male runners aged 18-25 years, who performing regular running at least 3 h/week during the past 2 (or more) years. Twenty healthy age-matched sedentary men were enrolled as a control group. The selection of the control group included those who do not perform any type of sport and do not walk more than 2 h/week. Participants were selected at the age of 18-25 years based on previously reported data, mentioning that PBM is attained during the second and third decades of life, and sports participation during this period may lead to adaptive changes that improve bone architecture through increased density and enhanced geometric properties.
Smoking, drinking more than two cups of coffee/day or alcohol consuming, body weight <60 kg or >80 kg, previous history of lower limb fracture, a family history of osteopenia or low impact fracture, endocrinal diseases, and those taking medication known to influence BMD. As these factors are known to affect BMD.
Demographic data and measurement of femoral BMD using DEXA were performed in all participates. The Z-score was selected for BMD assessment according to the International Society for Clinical Densitometry recommendation that states in men <50 years of age and children instead of t-score, ethnic, or race adjusted Z-score should be used. Serum calcium, phosphorous, testosterone, and osteocalcin levels were assessed. Exercise questionnaire for athletes including the duration of running (in years) and the average of running hours per week in the last 2 years was also done. Statistical analysis was carried out using SPSS statistics software version 17 , University of Cambridge Computing Service. Quantitative data were tested for normality using Kolmogorov-Smirnov test. Normally distributed variables were described using mean and standard deviation, and the independent sample t-test was used for comparing two groups. Pearson's correlation was used for testing correlations between quantitative variables. Statistical significance was accepted at P < 0.05. All applied statistical tests of significance were two-tailed.
| Results|| |
There was no significant difference regarding age, weight, height, and BMI between athletes and nonathletes [Table 1]. The duration of running among the studied runners ranged between 4 and 17 years and the average hours of running/week were 4-16 h/week [Table 2]. Regarding the laboratory findings, athletes had lower serum testosterone level compared to the control group, but higher serum osteocalcin [Table 1]. DEXA revealed that runners had higher BMD (at femoral neck, Ward's triangle, greater trochanter, and total femur) than nonrunners (P < 0.01), [Table 1]. A significant positive correlation was found between osteocalcin and BMD at the neck of femur and greater trochanter among runners [Figure 1]. A significant positive correlation was found between BMD (at the selected sites) and either the duration of running in years (r = 0.582, P = 0.007), or the mean hours of running/week in last the 2 years (r = 0.565, P = 0.009) among runners [Figure 2]a and b]. Significant positive correlation was found between serum osteocalcin level and both the duration of running in years (r = 0.808, P < 0.001), and the mean hours of running/week (r = 0.886, P < 0.01) [Figure 3]a and b. No significant correlation was found between BMD and either serum calcium, phosphorous, or testosterone levels in both groups.
|Figure 1: Scatter chart representation of the correlation between bone mineral density at the greater trochanter and the osteocalcin level among the runners|
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|Figure 2: Scatter chart representation of the correlation between bone mineral density at the greater trochanter and (a) duration of running in years, (b) the mean hours of running/week|
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|Figure 3: Scatter chart representation of the correlation between serum osteocalcin and (a) duration of running in years, (b) the mean hours of running/week|
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| Discussion|| |
In the current study, there was a significant increase in the femoral BMD (whether measured by g/cm2 or Z-score) in runners compared to nonrunners. This can be explained by the fact that biomechanically, the ward triangle, greater trochanter, and femoral neck are subjected to compressive and shear forces during running. These forces produce higher strain level and hence a greater osteogenic stimulus. The greatest differences between both groups were seen in the greater trochanter (t = 4.4), Ward's triangle (t = 4.3), neck of femur (t = 4.03), and to lesser extent in the total femur (t = 3.9). This result is in accordance with some previously published studies., The difference in the proximal femur sites (neck femur, Ward's triangle, and greater trochanter) compared to the total femur could be attributed to the fact that proximal femur contains predominantly trabecular bone that reacts more to the subjected strain. In the current study - based on the Z-score - the lowest scores in both groups were at the greater trochanter area. This finding may disagree with Mauck and Clarke who reported that the femoral neck was the gold standard for diagnosing osteopenia or osteoporosis. Further studies on a larger scale are recommended to confirm this result among Egyptian population.
Regarding laboratory results, the current study showed no significant difference between runners and nonrunners in serum calcium or phosphorus levels. This is in agreement with the finding of Marwaha et al. in 2011. In the present study, serum osteocalcin level was significantly higher in runners compared to nonrunners. This is consistent with the findings of some previous studies., Osteocalcin is the most important noncollagen protein in bone matrix. It is a bone-specific calcium binding protein, and it is Vitamin K dependent. It reflects the level of the osteoblastic activity in the bone and be related to the bone turnover. The higher osteocalcin level confirms the fact that exercise induces high osteoblastic activity and moreover decreases osteoclast surface of bone 10 days after loading.
Although serum testosterone (T) level was within the normal range in all runner subjects (normal range is 2.41-8.27 ng/ml), there was a significant lowered T-level in runners compared to these levels in nonrunners. There is a conflict in published researches regarding the T -level among athletes. Some studies showed similar results., This suppression was explained by them to be due to an alteration in the hypothalamic-pituitary-testicular regulatory axis since the LH of the endurance subjects was not elevated. However, MacKelvie et al., 2000, showed no difference between athletes and nonathletes as regarding serum T-level. Moreover, in a study published by Guglielmini et al., 1984, serum T increased by 38.2% in middle-distance runners. They attributed it to increased circulating lactate concentration, mediated by cyclic adenosine monophosphate in testicles. Lactate increases gonadotropin-releasing hormone and hence increases LH and T releases into blood stream. Furthermore, several studies have reported that the sympathetic nervous system could also take part to the hypersecretion of testosterone during exercise. Further studies with a larger number of participates are recommended to determine the effect of running on T-level.
The positive correlation between serum osteocalcin level and BMD among runners of this study indicates that running has a definite positive osteogenic effect. This agrees with the results of some previous studies., On the other hand, the lack of correlation between osteocalcin and BMD in nonrunners may probably be due to the fact that there is always physiological coupling between bone formation and bone resorption, and in athletes, exercise has the capacity to increase bone turnover, formation, and resorption, with preponderance on the rise of markers of formation.
The significant positive correlation between duration of running (years), or mean hours of running per week, and BMD suggest that BMD is related to the intensity of moderate exercise. In published literatures, one study agreed with this finding, other disagreed with it. The contrary results were explained by caloric insufficiency relative to energy expenditure among their selected subjects.
| Conclusion|| |
The present study further confirms the osteogenic effect of running on BMD; moreover, it supports the effect of running on bone cellular level as demonstrated by the high serum osteocalcin level among runners.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2]