Original Articles
Resistance training and bone mineral density in adolescent females,☆☆

https://doi.org/10.1067/mpd.2001.116698Get rights and content

Abstract

Objective: To examine the effects of 15 months of resistance training on bone mineral density (BMD) in female adolescents (aged 14 to 17 years). Study design: Participants were randomly assigned to either a training (n = 46) or control group (n = 21). BMD and body composition were measured by using dual-energy x-ray absorptiometry. Strength was assessed by means of one-repetition maximums for the leg press and bench press. The exercise group trained 30 to 45 minutes a day, 3 days per week, using 15 different resistance exercises. Control participants remained sedentary (<2 hours of exercise per week). Results: Leg strength increased significantly (40%) in the exercise group, but there were no changes in the control group. Femoral neck BMD increased significantly in the training group (1.035 to 1.073 g/cm2, P < .01) but not in the control group (1.034 to 1.048 g/cm2). No significant changes were seen in either group in lumbar spine BMD (1.113 to 1.142 g/cm2 and 1.158 to 1.190 g/cm2, respectively) or total body BMD (1.103 to 1.134 g/cm2 and 1.111 to 1.129 g/cm2, respectively). Conclusion: Resistance training is a potential method for increasing bone density in adolescents, although such a program would be best done as part of the school curriculum. (J Pediatr 2001;139:494-500)

Section snippets

Methods

Participants were between the ages of 14 and 17 years, with at least 2 years of regular menstrual cycles. Recruiting presentations were made at local high schools to all girls in the appropriate age groups. Girls participating in varsity sports were told they would not be eligible. Follow-up contact was initiated with 98 girls who indicated an interest in participating in the study. All participants were nonsmokers, were not pregnant, were engaged in <2 hours of physical activity per week, and

Results

At baseline, 21 participants entered the study as control subjects and 46 entered in the resistance training group. After 5 months, 6 participants had dropped out of the control group and 25 had dropped out of the resistance training group. At the 10-month assessment, 4 more control participants and 12 more exercisers had dropped out. At the end of the 15 months, there were 11 participants in the control group and 5 in the resistance training group. Participants who left the study cited lack of

Discussion

Adolescents represent a unique population in that, for the most part, they have not yet reached peak bone mass21, 22 and bone density is still increasing. Thus, it was unknown whether resistance training would provide a sufficient stimulus to increase BMD beyond what was naturally occurring, especially given the generally low calcium intake in this age group.23 The major finding of the present study was that 15 months of resistance training significantly increased femoral neck BMD in adolescent

Acknowledgements

We thank Bill Currie, Tammy Johnson, Kristi Lloyd, Rachel Morriss, Marilyn Heslip, Cathy Jacobson, Lori Moon, and Beki Garcia and Drs Vic Ben-Ezra, Kevin Kendrick, Beez Schell, Kathy Jankowski, Darla Smith, Sydney Bonnick, Nancy DiMarco, Linda King, and Sue Smith for help with this project.

References (33)

  • C Snow-Harter et al.

    Effects of resistance and endurance exercise on bone mineral status of young women: a randomized exercise intervention trial

    J Bone Miner Res

    (1992)
  • JC Rockwell et al.

    Weight training decreases vertebral bone density in premenopausal women: a prospective study

    J Clin Endocrinol Metab

    (1990)
  • EJ Bassey et al.

    Pre- and postmenopausal women have different bone mineral density responses to the same high-impact exercise

    J Bone Miner Res

    (1998)
  • LE. Lanyon

    Using functional loading to influence bone mass and architecture: objectives, mechanisms, and relationship with estrogen of the mechanically adaptive process in bone

    Bone

    (1996)
  • M Bradney et al.

    Moderate exercise during growth in prepubertal boys: changes in bone mass, size, volumetric density, and bone strength: a controlled prospective study

    J Bone Miner Res

    (1998)
  • FL Morris et al.

    Prospective ten-month exercise intervention in premenarcheal girls: positive effects on bone and lean mass

    J Bone Miner Res

    (1997)
  • Cited by (0)

    Supported by National Institutes of Health grant AR42728.

    ☆☆

    Reprint requests: David L. Nichols, PhD, Texas Woman’s University, PO Box 425876, Denton, TX 76204.

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