The Effects of a 12-Week Jump Rope Exercise Training Program on Arterial Stiffness, Vasodilating and Vasoconstricting Factors, Inflammatory Markers, and Body Composition in Prehypertensive Adolescent Girls
Phase: NA
Conditions: Prehypertension, Blood Pressure, Abdominal Obesity, Adiposity
Sponsor: Pusan National University

Document Date: 03/25/2019 
 
The Effects of a Jump Rope Exercise Program on Vascular Health, Inflammatory Markers 
in Prehypertensive Adolescent Girls: full study protocol and statistical analysis plan  
 
NCT#03534427 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

 
Study protocol 
Participants 
Forty girls (age 14-16) volunteered to participate in this research study. All participants were classified as 
prehypertensive (120-140 mmHg systolic BP and/or 80-90 mmHg diastolic BP) and had abdominal obesity (waist > 
80 cm, BMI equal to or greater than the 95th percentile for age and sex). All participants were considered to be 
inactive, meaning they participated in less than 1 hour of regular physical activity per week within the last 6 months. 
Other exclusion criteria included a previous musculoskeletal injury within the last year that may negatively affect 
participation, as well as cardiovascular, pulmonary, adrenal, pituitary, and thyroid diseases. Participants who were 
already involved in a regular exercise program, on daily medication(s), including antioxidants and fat loss 
supplements, or weight loss diet plans were also excluded from participation. All procedures performed in this study 
were in accordance with the ethical standards of the institutional research committee at Pusan National University 
(PNU IRB/2016_105_HR) and with the tenets of the Declaration of Helsinki. This study was registered in 
Clinicaltrials.gov (NCT03534427). Informed consent was obtained from all individual participants and their 
parent/guardian(s) included in this study. Participant characteristics can be seen in Table 1.  
Study design 
A two-armed, parallel experimental design was used. The jump rope exercise intervention took place during the 
months of March – June during the school year. Blood samples, anthropometrics, and vascular function parameters 
were assessed before (baseline) and after the 12-week jump rope exercise program at 8:00 AM (±1 hour) following 
an overnight fast. After baseline measurements were performed, the participants were randomly assigned to either 
the jump rope exercise group (EX, n = 20) or the control group (CON, n = 20). The participants in the EX group 
participated in an exercise program (50 minutes per day, 5 times per week for 12 weeks) that consisted of jump rope 
variations. Exercise was performed at 2:00PM (±1 hour) Monday-Friday. The EX group did not perform any 
additional exercise outside of this prescribed program during the 12 weeks. The participants in the CON group did 
not participate in the exercise intervention, or any outside exercise during the 12-week period, but were present and 
supervised in the laboratory at the same frequency, duration, and time of day as the EX group throughout the entire 
study period. Both groups of participants were advised weekly not to change their diet habits (~1920 kcal/day) for 
the duration of the study, and diet logs were obtained every week to keep track of dietary intake. Water intake was 
not recorded, however, participants were encouraged to consume approximately 2.5 liters of water per day (Sawka et 

al. 2005). All exercise sessions were supervised by trained professionals and all measurements were taken by 
qualified researchers.  
Blood sampling and analysis 
Blood samples were collected at 8:00 AM (±1 hour) after an overnight fast at baseline and after 12 weeks from an 
antecubital vein. Each sample was centrifuged for 15 minutes at 3,000 rpm stored at -80°C for later analysis. Using 
the provided reagents, each blood sample was run in duplicate in accordance with the manufacturer’s instructions for 
total nitrate and nitrite levels, which were analyzed using a Griess assay kit from Cayman Chemical (Ann Arbor, 
MI, USA) (Giovannoni et al. 1997). The amount of nitrate and nitrite produced in the reaction mixture was 
determined spectrophotometrically at 540 nm (OD540) using a microplate reader (Edwards et al. 2004; Masaki and 
Yanagisawa 1992). Levels of endothelin-1 (ET-1) in blood samples were measured with an enzyme immunoassay 
kit (Endothelin-1 Enzyme Immunoassay Kit, Cayman Chemical, Ann Arbor, MI, USA). The detection range for ET-
1 using this assay was from ≥ 1.5 μmol/mL (Hodeib et al. 2010). C-reactive protein (CRP) was assessed using an 
enzyme immunoassay kit (C-Reactive Protein Enzyme Immunoassay Kit, Cayman Chemical, Ann Arbor, MI, USA) 
according to the manufacturer’s instructions (Druwe et al. 2012).  
Pubertal Development 
Pubertal development was assessed using Tanner staging (breast and pubic hair stage) by self-reporting at the 
beginning of the study. Standard line drawings and written descriptions were provided, and participants selected the 
picture that most accurately reflected their appearance (Morris and Udry 1980). 
Anthropometrics 
Anthropometric measurements were taken at baseline and after 12 weeks. Height was measured without shoes using 
a stadiometer to the nearest 1.0 cm. Body composition was measured using bioelectrical impedance analysis (BIA) 
(InBody 230, Biospace, Seoul, Korea), which simultaneously recorded total body mass (nearest 0.1kg), percent body 
fat (nearest 0.1%), and fat-free mass (nearest 0.1 kg) (Seo et al. 2012). The InBody 230 specifically has been 
validated to be consistent with the doubly labeled water method (Beato et al. 2018) and dual x-ray absorptiometry 
for measurements of total fat mass, total lean mass, and percent body fat (Karelis et al. 2013). For BIA, the intra-
assay coefficient of variation (repeated measures within individual) was 0.8 ± 0.9% and the inter-assay coefficient of 
variation (repeated measures between different days) was 0.3 ± 0.2%. BMI was calculated as body mass divided by 
the square of height (kg/m2). Waist circumference was recorded using a standard tape measure to the nearest 0.1 cm 

at the midpoint between the iliac crest and the lower rib. These values were used to determine adiposity in absolute 
terms; however, there are no standard values that are considered to represent high adiposity in children and 
adolescents (Flegal et al. 2010).  
Vascular function 
Resting systolic and diastolic BP (mmHg) and resting heart rate (bpm) were both measured in duplicate using an 
automatic sphygmomanometer (HEM-7113 INT; Omron Corp., Kyoto, Japan) and radial artery palpation, 
respectively, at baseline and after 12 weeks. The measurements were recorded after participants were in a seated 
position for 5 minutes. The average of the two measurements was recorded as the resting BP and resting heart rate. 
Brachial-to-ankle pulse wave velocity (baPWV, m/s), an indicator of peripheral arterial stiffness, was measured 
using applanation tonometry (SphygmoCor CPV system, AtCor Medical Ltd, Sydney, Australia), followed by data 
analysis (version 8.0, SphygmoCor Cardiovascular Management Suite, AtCor Medical Ltd, Sydney, Australia). Two 
measurements were collected, one at each time point, and averaged as previously described (Weber et al. 2004; 
Yambe et al. 2007). 
Jump rope exercise program 
Participants in the EX group participated in a jump rope exercise program for 12 weeks, 5 days per week, for 50 
minutes per day (Table 2). This program was divided into a warm-up (5 minutes), the main exercise session (40 
minutes of rope jumping variations), and a cool-down (5 minutes). Both the warm-up and the cool-down consisted 
of stretching, walking, and jogging. There were 7 main rope jumping exercises, including 1 line 2 jump, jumping 
feet together, running jumping, open side jump, open back and forth jump, and rock paper scissor jump. The jump 
rope exercise program intensity incrementally increased every 4 weeks: weeks 1-4 were at 40-50% HRR and 11-12 
RPE, weeks 5-8 were at 50-60% HRR and 13-14 RPE, and weeks 9-12 were at 60-70% HRR and 15-16 RPE. These 
exercise intensities, frequencies, and durations were chosen to reflect previous studies that reduced fat mass, BP, and 
arterial stiffness in various populations (Arikawa et al. 2011; Beck et al. 2013; Ewart et al. 1998). The exercise 
intensity of the jump rope program was monitored using heart rate reserve (HRR) and Borg’s rating of perceived 
exertion scale (RPE) of 6-20. Participant heart rate was monitored using a wearable Polar heart monitor (Electro, 
Oy, Kempele, Finland) during all exercise sessions in order to sustain the proper training intensity. There were 5 
trainers supervising each exercise session, each specifically assigned to 4 participants. Heart rate monitors and RPE 

were checked every 5 minutes during the 40-minute training session. If heart rate or RPE were either too low or too 
high, participants were encouraged to either increase or decrease their effort during the session.  
Statistical analysis plan 
The Shapiro-Wilk test was used to determine the normality of the data. Independent t-tests were used to determine 
baseline differences between the two groups. A two-way analysis of variance (ANOVA) with repeated measures 
[group (CON and EX) x time (before and after 12 weeks)] was used to compare the difference of changes between 
pre- and post-jump rope exercise program within and between groups on the dependent variables. Bonferroni 
correction was used to determine the effects of the jump rope training program over time. When a significant main 
effect or interaction was noted, paired t-tests were used for post-hoc comparisons. An effect size analysis was 
performed using eta-squared (η2) for the two-way ANOVA, and interpreted 0.01, 0.06, and 0.14 as small, medium 
and large, respectively (Lee et al. 2018). Cohen’s d was used for the t-tests, interpreted as 0.20, 0.50, and 0.80 as 
small, medium and large, respectively (Lee et al. 2018). All analyses were performed using SPSS 25.0 (SPSS Inc., 
Chicago, IL, USA). Data are presented as Mean ± SD. Statistical significance was set at P ≤ 0.05. It was estimated 
that 40 participants would enable 80% power to detect a 5% decrease in baPWV after the jump rope exercise 
program based on previous literature (Figueroa et al. 2011).