Michael J. Rebold

The relationship between cell phone use, physical and sedentary activity, and cardiorespiratory fitness in a sample of U.S. college students

BackgroundToday’s cell phones increase opportunities for activities traditionally defined as sedentary behaviors (e.g., surfing the internet, playing video games). People who participate in large amounts of sedentary behaviors, relative to those who do not, tend to be less physically active, less physically fit, and at greater risk for health problems. However, cell phone use does not have to be a sedentary behavior as these devices are portable. It can occur while standing or during mild-to-moderate intensity physical activity. Thus, the relationship between cell phone use, physical and sedentary activity, and physical fitness is unclear. The purpose of this study was to investigate these relationships among a sample of healthy college students.MethodsParticipants were first interviewed about their physical activity behavior and cell phone use. Then body composition was assessed and the validated self-efficacy survey for exercise behaviors completed. This was followed by a progressive exercise test on a treadmill to exhaustion. Peak oxygen consumption (VO2 peak) during exercise was used to measure cardiorespiratory fitness. Hierarchical regression was used to assess the relationship between cell phone use and cardiorespiratory fitness after controlling for sex, self-efficacy, and percent body fat. Interview data was transcribed, coded, and Chi-square analysis was used to compare the responses of low and high frequency cell phone users.ResultsCell phone use was significantly (p = 0.047) and negatively (β = −0.25) related to cardio respiratory fitness independent of sex, self-efficacy, and percent fat which were also significant predictors (p < 0.05). Interview data offered several possible explanations for this relationship. First, high frequency users were more likely than low frequency users to report forgoing opportunities for physical activity in order to use their cell phones for sedentary behaviors. Second, low frequency users were more likely to report being connected to active peer groups through their cell phones and to cite this as a motivation for physical activity. Third, high levels of cell phone use indicated a broader pattern of sedentary behaviors apart from cell phone use, such as watching television.ConclusionCell phone use, like traditional sedentary behaviors, may disrupt physical activity and reduce cardiorespiratory fitness.

The impact of cell phone use on the intensity and liking of a bout of treadmill exercise.

This study used a within-subjects design to assess the effect of three common cellular telephone (cell phone) functions (texting, talking, listening to music) on planned exercise. Forty-four young adults (n = 33 females, 21.8 ± 1.3 years) each participated in four, separate, 30-minute exercise conditions on a treadmill in a random order. During each condition, the treadmill speed display was covered and grade was fixed at zero. However, participants were able to alter treadmill speed as desired. Throughout the texting and talking conditions, research personnel used a pre-determined script to simulate cell phone conversations. During the music condition, participants used their cell phone to listen to music of their choice. Finally, participants completed a control condition with no cell phone access. For each condition, average treadmill speed, heart rate and liking (via visual analog scale) were assessed. Treadmill speed (3.4 ± 1.3 miles∙hour-1), heart rate (122.3 ± 24.3 beats∙min-1) and liking (7.5 ± 1.5 cm) in the music condition were significantly (p ≤ 0.014) greater than all other conditions. Treadmill speed in the control condition (3.1 ± 1.2 miles∙hour-1) was significantly (p = 0.04) greater than both texting and talking (2.8 ± 1.1 miles∙hour-1 each). Heart rate during the control condition (115.4 ± 22.8 beats∙min-1) was significantly (p = 0.04) greater than texting (109.9 ± 16.4 beats∙min-1) but not talking (112.6 ± 16.1 beats∙min-1). Finally, liking during the talking condition (5.4 ± 2.2 cm) was greater (p = 0.05) than the control (4.3 ± 2.2 cm) but not the texting (5.1 ± 2.2 cm) conditions. In conclusion, using a cell phone for listening to music can increase the intensity (speed and heart rate) and liking of a bout of treadmill exercise. However, other common cell phone uses (texting and talking) can interfere with treadmill exercise and reduce intensity.

The impact of cell phone texting on the amount of time spent exercising at different intensities

This study assessed the effect of cell phone texting during a 30-min bout of treadmill exercise on the amount of time spent exercising at different intensities. Thirty-two college students participated in two conditions (cell phone and control). During the cell phone condition participants could use their cell phone only for texting purposes. During the control condition participants did not have access to their cell phone nor any interaction with other individuals or electronics. Heart rate was measured continuously and was used to determine how much time was spent exercising at different intensities. Vigorous intensity minutes was significantly greater (p?=?0.001) in the control condition (12.94???8.76?min) than the cell phone condition (7.09???8.38?min). Low intensity minutes was significantly greater (p?=?0.001) in the cell phone condition (9.47???9.73) than the control condition (3.44???6.52). Moderate intensity minutes in the cell phone (13.44???8.43) and control (13.69???8.13) conditions were not significantly (p?=?0.89) different. In conclusion, using a cell phone for texting can interfere with treadmill exercise by promoting greater participation in low intensity exercise and less participation in vigorous intensity exercise due to a possible dual-tasking effect. Cell phone texting during treadmill exercise was examined.Texting during exercise increases the time spent exercising at a low intensity.No cell phone during exercise increases participation in high intensity exercise.Altered exercise intensities may have important implications on health and fitness.

The influence of a Tabata interval training program using an aquatic underwater treadmill on various performance variables.

Abstract Rebold, MJ, Kobak, MS, and Otterstetter, R. The influence of a Tabata interval-training program using an aquatic underwater treadmill on various performance variables. J Strength Cond Res 27(12): 3419–3425, 2013—The purpose of this study was to investigate the effects of an 8-week aquatic treadmill running (ATM) Tabata interval-training program on various performance variables including body fat percentage, force production, flexibility, and anaerobic power. Totally, 25 participants (17 males and 8 females) were randomized into either a control group (CON), which only completed Pre- and Posttesting, or exercise group (EX), which took part in the 8-week ATM Tabata interval-training program. Pre- and Posttesting consisted of the following measurements: body fat percentage, flexibility, force production, and anaerobic power. The Tabata interval-training program consisted of sprinting on an ATM at 7.5 miles⋅h−1 and with the front jets turned on at 80, 85, 90, and 95% progressively increasing throughout the 8 weeks. A 2-way repeated measures analysis of variance revealed a significant effect of time (F = 236.13; p < 0.001) and group by time interaction (F = 1.95; p = 0.02). Paired-samples t-test revealed a significant difference in the CON group from Pre- to Posttesting for mean power from the Wingate test (t = −2.20; p = 0.05) and a significant difference in the EX group for right leg goniometry (t = −2.34; p = 0.04) and mean power from the Wingate test (t = −2.81; p = 0.02). These results are favorable because it demonstrates that participants who engage in an ATM Tabata interval-training program can elicit a strong enough stimulus to improve flexibility and anaerobic power in terms of mean power while decreasing musculoskeletal impact placed on the ligaments, joints, and tendons.