**2. Methods**

### **2.1 Participants**

This cross-sectional study included volunteer participants from selected secondary schools in Benue State, North Central Nigeria. Participants were eligible to participate in the study if they had no musculoskeletal problems, history of CVD, other reported health problems and sickness or had not participated in organized exercise programs at least 6 months before data collection. The study purpose and test procedures were fully explained to participants after permission was duly obtained from the heads of participating schools. The study protocol was approved by the health research ethics committee of Benue State University (Ref. No. BSUTHMKD/HREC/2013/017). Written informed consent of parents/guardians and assent of participants were sought before data collection. All tests were conducted in accordance with the ethical guidelines of the Helsinki declaration.

### **2.2 Study setting**

The present study was conducted among adolescents aged 12–16 years in the three senatorial districts of Benue State, Nigeria (Benue North, Benue Central, and Benue South). Benue state with its capital at Makurdi is located in the North central geopolitical zone of Nigeria. The predominant tribes are Tivs, Idomas, Igedes and Etulos. The study

covered 11 secondary schools comprising 2100 adolescent girls and boys. Like any typical state in Nigeria, secondary schools in Benue State are in two main categories: public and private. The public schools are owned by the government while private schools are owned by private individuals and Christian missionaries. The schools start lessons by 8:00 am and close by 2:00 pm with a 45 minutes break at 10 am.

### **2.3 Physical characteristics measurement**

Participants' physical characteristic measurements were in accordance with the protocol of the International Society for the Advancement of Kinanthropometry (ISAK) [11]. Specifically, bare-foot body mass and stature were measured in light clothing without shoes and socks with the aid of a calibrated digital weighing scale (Model Sec-880, Seca Birmingham, UK) and wall-mounted stadiometer (Model Sec-206; Seca, Birmingham, UK) to the nearest 0.1 kg and 0.1 cm, respectively. BMI was computed by dividing body mass in kilograms by stature in meter-square (kg. m−2). BMI was used to estimate body fatness. Body fat was estimated from triceps and medial calf skinfolds with the aid of Harpenden skinfold calipers (Creative Health Products, Ann Arbor, MI, USA). Measurements were taken three times on the right side of a participant's body and the median was recorded. The revised regression equations for black children were used to estimate percent body fat [12]. On the basis of their BMI values, participants were categorized into healthy weight (HW) and overweight (OW) according to FitnessGram revised data [12].

Waist circumference (WC) which estimates abdominal fat [13] was measured with a Lufkin non-extensible flexible anthropometric tape (W606PM Rosscraft, Canada) to the nearest 0.1 cm. Details of the measurement procedure have been previously described [7]. All physical characteristics measurements were conducted by an accredited ISAK-Certified level 2 Anthropometrist (Lead author).
