High-Intensity Interval Training Interventions in Children and Adolescents: A Systematic Review.

Eddolls WTB, McNarry MA, Stratton G, Winn CON, Mackintosh KA.
Sports Med. 2017 Nov;47(11):2363-2374. doi: 10.1007/s40279-017-0753-8.

BACKGROUND: Whilst there is increasing interest in the efficacy of high-intensity
interval training in children and adolescents as a time-effective method of
eliciting health benefits, there remains little consensus within the literature
regarding the most effective means for delivering a high-intensity interval
training intervention. Given the global health issues surrounding childhood
obesity and associated health implications, the identification of effective
intervention strategies is imperative.
OBJECTIVES: The aim of this review was to examine high-intensity interval
training as a means of influencing key health parameters and to elucidate the
most effective high-intensity interval training protocol.
METHODS: Studies were included if they: (1) studied healthy children and/or
adolescents (aged 5-18 years); (2) prescribed an intervention that was deemed
high intensity; and (3) reported health-related outcome measures.
RESULTS: A total of 2092 studies were initially retrieved from four databases.
Studies that were deemed to meet the criteria were downloaded in their entirety
and independently assessed for relevance by two authors using the pre-determined 
criteria. From this, 13 studies were deemed suitable. This review found that
high-intensity interval training in children and adolescents is a time-effective 
method of improving cardiovascular disease biomarkers, but evidence regarding
other health-related measures is more equivocal. Running-based sessions, at an
intensity of >90% heart rate maximum/100-130% maximal aerobic velocity, two to
three times a week and with a minimum intervention duration of 7 weeks, elicit
the greatest improvements in participant health.
CONCLUSION: While high-intensity interval training improves cardiovascular
disease biomarkers, and the evidence supports the effectiveness of running-based 
sessions, as outlined above, further recommendations as to optimal exercise
duration and rest intervals remain ambiguous owing to the paucity of literature
and the methodological limitations of studies presently available.