The Effects of Low Energy Availability and High Impact Jumping on Markers of Bone (re)Modelling in Females

Summary

Osteoporosis is worldwide health epidemic categorized by poor bone health, primarily diagnosed by low bone mineral density, and costs healthcare systems billions every year. Athletes and exercising people who expend large amounts of energy in physical activity, or restrict diet in order to lose weight, are at risk of low energy availability. This is when an individual fails to match their exercise energy demand with a appropriate dietary intake in order to maintain optimal physiological function; which can lead to low bone mineral density, osteoporosis both early and later in life and an increased risk of injury. Runners are particularly susceptible to stress fracture in response to low energy availability due to repetitive ground impact. Research shows that as little as five days low energy availability significantly reduces bone formation, and significantly increases bone resorption, in physically active women. The ideal solution is to restore energy availability; however, this is often very difficult during periods of intense training and conflicts with the goal of weight loss. Therefore, there is a need to develop an alternative tool to protect bone health. It is critical that any exercise intervention does not further reduce energy availability as previous research shows that this accelerates bone loss rather than prevents it. Low repetition high impact jumping exercise is highly beneficial to bone health and has been shown to improve bone structure when used as a long-term intervention in energy replete states. It takes very little time to complete and uses a very small amount of energy. However, no study to date has examined the effects of such an intervention during low energy availability. The current study will investigate whether low repetition high impact jumping prevents or reduces the reduction in bone formation and the increase in bone resorption experienced during five days of low energy availability and findings will have implications on athletic and recreational training recommendations in order to protect bone health.

Conditions

• Bone Resorption
• Bone Atrophy
• Energy Supply; Deficiency
• Female Athlete Triad
• Relative Energy Deficiency in Sport

Interventions

BEHAVIORAL

Low energy availability

Participants will be provided with food to eat every day and will not be permitted to consume any other calorie containing foods or beverages. This amount of energy contained within the food provided will be one third of that contained in the food provided in the control condition (45 kilo-calories per kilogram of fat-free mass per day) and will be standardized between and within participants for carbohydrate, protein and fat composition.

BEHAVIORAL

High impact jumping

Participants will perform a brief session of high impact jumping every morning (10 maximum effort vertical counter-movement jumps, and 5 maximum effort lateral drop jumps in each direction) and a similar session of high impact jumping every evening (20 maximum effort vertical counter-movement jumps).

Sponsors & Collaborators

• Loughborough University

  lead OTHER

Principal Investigators

• Richard C Blagrove, PhD · Loughborough University

• Emma O'Donnell, PhD · Loughborough University

• Katherine SF Brooke-Wavell, PhD · Loughborough University

Study Design

Allocation

RANDOMIZED

Purpose

PREVENTION

Masking

NONE

Model

CROSSOVER

Eligibility

Min Age

18 Years

Max Age

35 Years

Sex

FEMALE

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2020-11-01

Primary Completion

2022-06-30

Completion

2022-06-30

Countries

• United Kingdom

Study Locations