The Effects of Short-term Low Energy Availability and Low Repetition High Impact Jumping on Markers of Bone Formation and Resorption in Young Females
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 入组人数
- 19
- 试验地点
- 1
- 主要终点
- Change in blood pro-peptide of type 1 collagen (P1NP) concentration
研究概览
简要总结
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.
详细描述
Participants will complete two four-day experimental conditions within the first seven days of two separate menstrual cycles. These will be preceded by a four-day baseline assessment period. There are three experimental conditions in total: control (CON), low energy availability (LEA) and low energy availability and high impact jumping (LEA+J). Participants will be randomly allocated to complete the control condition and either the LEA or LEA+J condition. The order in which the two conditions are completed will be randomized and counterbalanced. In total, fifteen laboratory visits will be required per participant:
Baseline assessment (four days and one visit):
Visit 1:
Participants will come to the laboratory to complete the informed consent procedure on day 1, once they have had at least 24 hours to consider the participant information sheet. Providing informed consent is given, participants will complete three questionnaires (a health screen, the Low Energy Availability in Females Questionnaire and the International Physical Activity Questionnaire) which include questions regarding their medical and injury history, dietary habits, menstrual cycle and physical activity habits. They will then have their height and weight taken. Provided the responses and measures confirm that the participant meets the inclusion and exclusion criteria, they will then undergo familiarization of resting metabolic rate assessment where they will lay supine in a dimly lit room whilst expired gas is collected via a mouthpiece. During familiarization the researcher will check for signs of hyperventilation. Following that, the participants will be familiarized with a jumping exercise routine if the participant is randomized into the group that will be performing this routine during an experimental condition. Finally, the participant will be asked to complete an incremental exercise test to volitional exhaustion on a treadmill whilst expired gas is collected and analysed using a metabolic cart, and heart rate and rating of perceived exertion are taken, as a measure of aerobic fitness.
For the following three days (2, 3 and 4), participants will be instructed to self-report weighed energy intake using a set of scales provided and a food diary according to the instructions on the diary itself which the researcher will read through with the participant. They will be asked to eat according to their usual dietary habits and return it electronically at the end of day 4, or during a subsequent visit. Participants will also be provided with a tri-axial accelerometer (Actigraph GT3X+) device and instructed to wear it around the waist for the entirety of days 2, 3 or 4 (apart from when bathing and washing). They will be not required to visit the laboratory on days 2, 3 or 4.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Crossover
- 主要目的
- Prevention
- 盲法
- None
入排标准
- 年龄范围
- 18 Years 至 35 Years（Adult）
- 性别
- Female
- 接受健康志愿者
- 是
入选标准
- •To take part in this study, the following inclusion criteria must be met:
- •Menstrual cycles that are between 21 - 35 days in length for at least the previous three cycles
- •Regular length of menstrual cycle (less than six days difference between cycles) for at least the previous three cycles
- •Body mass index between 18.5 - 30 kg.m squared
- •Weight stable for the past three months and not currently dieting
- •Participants will not be able to take part in this study if any of the following
排除标准
- •Have used hormonal contraception at any point within the previous three months
- •Regularly engage in >3 vigorous, or >5 moderate, exercise sessions a week
- •Compete regularly in a high or multi-directional impact sport at national level or higher
- •Have sustained a bone injury within the previous twelve months
- •Have sustained any injury within the past six months that restricted their ability to exercise
- •Taken hormone replacement therapy (HRT) at any point during the past three months
- •Have been previously diagnosed with an eating disorder
- •Have taken any medications (other than vitamin or mineral supplements) known to effect bone metabolism within the previous three months (e.g. glucocorticoids, anticonvulsants or anabolic steroids)
- •Have previously been diagnosed with a medical condition known to impact bone health (e.g. hypothyroidism, hyperthyroidism, diabetes mellitus, hypercortisolism and renal or gastrointestinal disease)
- •Have previously been diagnosed with a pathology known to impact menstrual function (e.g. primary ovarian insufficiency, hyperprolactinemia, thyroid dysfunction, polycystic ovarian syndrome and any other conditions of androgen excess)
研究组 & 干预措施
Low energy availability
Intervention involves three of dietary energy restriction providing 15 kilo-calories per kilogram of fat-free mass per day.
干预措施: Low energy availability (Behavioral)
Low energy availability and high impact jumping
Intervention involves three days of dietary energy restriction providing 15 kilo-calories per kilogram of fat-free mass per day and brief high impact jumping exercise performed daily in the morning and in the evening.
干预措施: Low energy availability (Behavioral)
Low energy availability and high impact jumping
Intervention involves three days of dietary energy restriction providing 15 kilo-calories per kilogram of fat-free mass per day and brief high impact jumping exercise performed daily in the morning and in the evening.
干预措施: High impact jumping (Behavioral)
结局指标
主要结局
Change in blood pro-peptide of type 1 collagen (P1NP) concentration
时间窗: of dietary provision to the same time on the morning following the final day of dietary provision (three days later), in each condition
P1NP is a marker of bone resorption and it will be measured during the fasted state
Change in blood β-carboxyl-terminal cross-linked telopeptide of type 1 collagen (β-CTx) concentration
时间窗: of dietary provision to the same time on the morning following the final day of dietary provision (three days later), in each condition
β-CTx is a marker of bone formation and it will be measured during the fasted state
次要结局
- Change in blood 17β-oestradiol concentration(of dietary provision to the same time on the morning following the final day of dietary provision (three days later), in each condition)
- Change in body weight(of dietary provision to the same time on the morning following the final day of dietary provision (three days later), in each condition)
- Change in blood triiodothyronine (T3) concentration(of dietary provision to the same time on the morning following the final day of dietary provision (three days later), in each condition)
- Change in blood β-hydroxybutyrate (β-OHB) concentration(of dietary provision to the same time on the morning following the final day of dietary provision (three days later), in each condition)
- Change in the spectral density of heart rate variability in low and high frequency bands(of dietary provision to the same time on the morning following the final day of dietary provision (three days later), in each condition)
- Change in blood magnesium concentration(of dietary provision to the same time on the morning following the final day of dietary provision (three days later), in each condition)
- Change in blood phosphorus concentration(of dietary provision to the same time on the morning following the final day of dietary provision (three days later), in each condition)
- Change in ratio of measured:predicted resting metabolic rate (RMR)(From the morning of the first day of dietary provision to the same time on the morning following the final day of dietary provision (five days later), in each condition)
- Change in blood calcium concentration(of dietary provision to the same time on the morning following the final day of dietary provision (three days later), in each condition)
- Change in blood plasma volume (estimated using haemoglobin concentration and haematocrit)(of dietary provision to the same time on the morning following the final day of dietary provision (three days later), in each condition)
- Change in aortic stiffness(of dietary provision to the same time on the morning following the final day of dietary provision (three days later), in each condition)
- Change in forearm peak blood flow(of dietary provision to the same time on the morning following the final day of dietary provision (three days later), in each condition)
- Change in resting metabolic rate (RMR)(From the morning of the first day of dietary provision to the same time on the morning following the final day of dietary provision (three days later), in each condition)
- Change in heart rate variability(of dietary provision to the same time on the morning following the final day of dietary provision (three days later), in each condition)
- Change in baroreflex sensitivity(of dietary provision to the same time on the morning following the final day of dietary provision (three days later), in each condition)
- Change in forearm resting blood flow(of dietary provision to the same time on the morning following the final day of dietary provision (three days later), in each condition)
- Change in fat-free mass(of dietary provision to the same time on the morning following the final day of dietary provision (three days later), in each condition)
研究者
Katherine Brooke-Wavell
Principle Investigator
Loughborough University