In "undulating periodization" the manipulation of training volume and training load is on a weekly basis; light and heavy weekly training days.
The elevated risk of substance use among adolescents in RYC/SE was in some cases particularly marked for those who would normally be at lower risk for substance use (girls in SEB for heavy alcohol drinking and cannabis use, ethnic minority adolescents and adolescents with a stable family situation in RYC for respectively heavy weekly alcohol drinking and daily use of tobacco).
Only the combined intervention showed a significant effect on the reduction of weekly and heavy weekly drinking.
Heavy weekly alcohol consumption before pregnancy (≥8 units/week) was the variable with the highest odds estimate for binge drinking (aOR 32.63, CI: 19.23-55.36).
Boys in SEB were not significantly at higher risk for heavy weekly drinking as compared to boys in mainstream education; however, for girls in SEB the risk of heavy weekly drinking was much higher as compared to girls in mainstream education (OR = 5.05, CI = 2.95 8.67).
The cut-off point for heavy weekly alcohol consumption was calculated based on frequency, quantity and type of consumption, according to the World Health Organization (WHO) recommendations (see Additional file 1).
The risk of heavy weekly drinking among Dutch adolescents in RYC was somewhat higher as compared to those in mainstream education (OR = 1.81, CI = 1.33 2.45); however, among ethnic minorities, this risk was more elevated (OR = 4.92, CI = 2.72 8.90).
Hence, in this study boys who drank more than ten alcoholic beverages per week and girls who drank more than eight alcoholic beverages per week were identified as heavy weekly alcohol drinkers.
In the first model, the association between substance use (daily use of tobacco, heavy weekly alcohol drinking, lifetime prevalence of cannabis use and lifetime prevalence of hard drug use) and group membership (RYC, SEB, SEL, with mainstream education being the reference group) was tested.
The meta-analysis included a very large Canadian general-population survey in which risks of eating disorders also were associated with heavier weekly drinking among women ages 15 to 44 (Piran and Gadalla 2007).
