Impact Loading and Nutrition in Cyclists

I presented the findings of my research during a thematic poster session on “Energy Availability” at the 60th Annual Meeting of the American College of Sports Medicine held at the Indiana Convention Center in Indianapolis, Indiana, June 1, 2013. The abstract was published in Medicine and Science in Sports and Exercise, Volume 45:5 Supplement.

Impact Loading and Nutrition in Cyclists: A Clinical Intervention to Enhance Bone Mass

The purpose of this clinical intervention was to increase aBMD of  23 elite-level cyclists through a standardized jumping program in combination with individualized meal plans created to maintain energy balance or increase energy availability defined by energy intake minus resting and exercise energy expenditure. The jumping program and meal plans were used in combination with Vitamin D and Calcium supplementation when necessary to increase bone mass.

The methodology required an initial consultation during which I collected biochemical, clinical, and environmental data for our intake assessment form. I met with each of the 23 subjects (elite cyclists) who agreed to participate in the research study to discuss the protocols for logging their food and exercise using the website Since some subjects were unfamiliar with this website, I provided a brief tutorial and created instructional guides for them to keep.  Each subject was required to complete a weekly protocol of vertical jumps, log their meals and training three days per month, note their menstrual cycles, and get Vitamin D (25[OH]D), IGF-1, Testosterone, Estradiol, and Serum Ferritin measured with a Complete Blood Count. Pre and post-testing used DXA for measurement of bone mass, fat free mass, lean, and total mass, and a Vertec to measure height of vertical jump.

As a previous bike racer, I was able to build a relationship through my understanding of cycling equipment (power meter), the physiology of cycling performance, and nutrition/weight concerns of cyclists. Throughout the course of the study I provided feedback, support, and motivation for subjects to encourage thorough reporting and commitment to the study.

I co-lead phase 1 of this thesis, in support of my colleague (not a cyclist), and because I was the only person who used Training   To assist with Phase 1 of the study, I created the following documents:

  • Phase 1: Instructions & Training Peaks User Guide for Subjects
  • Phase 1: Slide presentation: My role in Phase 1 of the study
  • Phase 1: Recruitment Flyer 

Phase 2 of the Study: I was lead investigator of this phase of the study.

Subjects: Were recruited from Phase 1 (n=10, 5= male, 5 = female)

Methods: Continued the maximum jumping protocol. This included a 3 week progressive increase in jumps from 5 jumps/day – 3 days/week, to 5 jumps/day – 5 days/week, to 10 jumps/day – 5 days/week. This equalled 50 jumps/week from weeks 3 – 16 of the study.

  • Each athlete was required to continue food and exercise logging three days per month
  • Weekly logging of their jumps
  • Weekly logging of Vitamin D & Calcium supplementation
  • Three blood draw were conducted to measure: Vitamin D, Cortisol, CBC, Ferritin, Estradiol, Testosterone, and IGF-1.

Goal of Phase 2 of the study: Increase bone density through a combination of the same vertical jumping protocol, individualize customized periodized menu for athletes based upon their estimated energy expenditure to improve or maintain energy balance, Vitamin D3 and Calcium supplementation.
In addition to looking at changes in BMD over time, I also examined the influence of the following factors:

  • Low energy availability [EA],
  • Insulin like growth factor-1 [IGF-1],
  • Vitamin D status [25(OH)D],
  • Dietary/supplemental calcium and vitamin D intake

Phase 2 of the study:

  • Sample Meal Plans customized based upon:
    • energy expenditure (calculated using power meters, heart rate monitors, METS),
    • RMR (Cunningham and physiologic testing in lab),
    • subject food logs, and
    • periodization of their training season.
  • Handouts that included  a list of which foods to increase/decrease depending upon the intensity/volume of training (Easy, Medium,Hard)
  • Handouts of how to adjust ratio of macronutrients per meal (images of various plates and percentages of portions)
  • Each subject received a final handout that showed changes in all serum values, % jumps completed, meal comparisons, from phase 1 to phase 2