Understanding Treatment Response Heterogeneity Using Crossover Randomized Controlled Trials: A Primer for Exercise and Nutrition Scientists.

Crossover randomized controlled trials (RCTs) are common in exercise and nutrition sciences. Since researchers randomize participants to different sequences of the treatment and comparator/control conditions, crossover RCTs are powerful for detecting mean treatment effects under certain circumstances. We aim to review the information that can be derived from crossover RCTs about treatment response heterogeneity-a fundamental issue in precision medicine for tailoring treatments to individuals.

Ketone ester ingestion increases exogenous carbohydrate storage and lowers glycemia during post-exercise recovery: a randomised crossover trial.

β-hydroxybutyrate can suppress endogenous glucose production, with potential implications for carbohydrate metabolism during post-exercise recovery. The aim of the current study was to assess the effects of ketone ester ingestion during post-exercise recovery, on carbohydrate metabolism and subsequent exercise capacity. Thirteen endurance-trained men (age: 18-61 years, maximal aerobic capacity: 50 to 73 mL kg min) completed two conditions in a randomized crossover design.

The effectiveness of unsupervised home-based exercise for improving lower extremity physical function in older adults in Western and Eastern cultures: a systematic review and meta-analysis.

Background: Ageing leads to decreased physical function, which can impact independent living and raise health risks, increasing demand on healthcare resources. Finding affordable and accessible exercise to improve physical function is necessary for a population seemingly resistant to strength and balance training in leisure settings. This review aimed to evaluate whether unsupervised home-based exercises improve lower extremity function in older adults.

Effect of high-intensity interval training on cardiometabolic component risks in persons with paraplegia: Results of a randomized controlled trial.

The aim of this work is to determine the effect of upper-body high intensity interval training (HIIT) on cardiometabolic risks in individuals with chronic paraplegia. Twenty-seven individuals (14 females, 13 males, mean ± SD age: 46 ± 9 years) with chronic paraplegia (spinal cord injury between T2 and L5 >1-year post-injury) took part in a randomized controlled trial and were included in the final analysis. Participants in the HIIT group (n = 18) performed ∼30 min of arm crank exercise (60 s intervals at 80%-90% peak heart rate) four times per week, for 6 weeks.

The effects of dietary nitrate ingestion on physical performance tests in 50-65 years old postmenopausal women: A pilot randomized, double-blind, placebo-controlled, and crossover study.

Background & Aims: The post-menopausal period represents a noteworthy stage in a woman's life characterized by hormonal shifts that can influence diverse biological processes encompassing energy metabolism and physical performance. NO effects on physical performance in 50-65 years old postmenopausal women after short-term supplementation remain unknown.

Methods: This is a randomized, double-blind, placebo-controlled, crossover study.

Myths and Methodologies: Standardisation in Human Physiology Research-Should We Control the Controllables?

The premise of research in human physiology is to explore a multifaceted system whilst identifying one or a few outcomes of interest. Therefore, the control of potentially confounding variables requires careful thought regarding the extent of control and complexity of standardisation. One common factor to control prior to testing is diet, as food and fluid provision may deviate from participants' habitual diets, yet a self-report and replication method can be flawed by under-reporting.

Myths and Methodologies: Standardisation in human physiology research-should we control the controllables?

The premise of research in human physiology is to explore a multifaceted system whilst identifying one or a few outcomes of interest. Therefore, the control of potentially confounding variables requires careful thought regarding the extent of control and complexity of standardisation. One common factor to control prior to testing is diet, as food and fluid provision may deviate from participants' habitual diets, yet a self-report and replication method can be flawed by under-reporting.