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International Journal of Exercise Science

Recent documents in International Journal of Exercise Science

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Selecting the Best of the Best: Associations between Anthropometric and Fitness Assessment Results and Success in Police Specialist Selection

Thu, 19 Apr 2018 16:43:21 PDT

International Journal of Exercise Science 11(4): 785-796, 2018. To successfully complete specialist police selection, officers must be physically fit. The aim of this study was to investigate the relationship between performance on selected anthropometric and fitness tests and successful selection into a specialist police unit. Thirty-two male police officers (mean age = 29.48±4.99 years) participated in a Barrier Fitness Assessment (BFA), followed by a Specialist Selection Course (SSC). The BFA spanned two consecutive days of testing (pull-ups, push-ups, seven-stage sit-ups, a timed loaded pack march, a Multi-Stage Fitness Test, an agility run, a lift and carry task and a 300m swim assessment). The SSC occurred 4 weeks later and consisted of 8 days of intense police training. Officers who successfully completed the SSC were graded based on their performance and this determined their ultimate selection. Data were categorized into four participant groups: Group 1 - Did not complete the BFA; Group 2 - Completed the BFA but not the SSC; Group 3 - Completed the SSC and were not selected; and Group 4 - Completed the SSC and were selected. A Spearman’s rank order correlation analysis was conducted to assess the strengths of the relationships between selection stage achieved and scores on each of the predictor variables, with significance set at 0.05. Height (p=0.011), body weight (p=0.011), pull-ups (p=0.021) and push-ups (p=0.016), seven-stage sit-up scores (p=0.042) and lift and carry speed (p=0.010) were significantly and positively correlated with level of selection success. Results suggest that candidates wishing to attempt selection into specialist police units would benefit from being tall and training to optimize musculoskeletal strength and muscular endurance.

Carbohydrate Mouth Rinse Improves Relative Mean Power During Multiple Sprint Performance

Wed, 11 Apr 2018 12:39:38 PDT

International Journal of Exercise Science 11(6): 754-763, 2018. Multiple investigations have confirmed carbohydrate mouth rinse (CMR) enhances high intensity endurance performance lasting under 1 hour, but the effects of CMR on high intensity intermittent exercise has received less attention. This study examined the effect of CMR on high intensity multiple sprint performances in a protocol designed to emulate a cyclocross or mountain biking event. Seven trained men (28.2 ± 6.8 years, 185 ± 9 cm, 85.3 ± 14.8 kg, VO2peak 51.4 ± 7.3 ml/kg*min-1) completed two, 48 min high intensity intermittent cycling protocols that consisted of 6 bouts of 5 min cycling at 50% VO2 peak followed by sets of three, 10-s Wingate sprints with 50 s of recovery between sprints. Prior to each set of Wingate sprints, either a 6.4% carbohydrate solution (CMR) or placebo (PLA) were rinsed for 10 s using a counterbalanced crossover design. There was a significant main effect (CMR 10.51 ± 0.82, PLA 10.33 ± 0.87 W/kg; p < 0.05 ES=0.21) for mean power, but post hoc tests only revealed statistically significant performance improvement with CMR during the 6th bout (CMR 10.5 ± 0.75, PLA 10.22 ± 0.92 W/kg; p = 0.01 ES=0.33). No treatment effect was exhibited for peak power, fatigue index, ratings of perceived exertion, or blood glucose. Most team sport situations provide multiple opportunities for access to beverages, but gastrointestinal distress associated with fluid intake may reduce desire for significant beverage consumption. Under such circumstances, a small but practical ergogenic advantage may be exhibited if the fluid rinsed in the mouth contains carbohydrates.

Attitudes Towards Sports Concussion in Australian Exercise Science Students. Does the Type and Level of Participation in Sport Matter?

Tue, 10 Apr 2018 07:48:43 PDT

International Journal of Exercise Science 11(5): 739-753, 2018. Concussion in sport is a growing public health issue. However, research suggests that under-reporting of concussion by student-athlete cohorts reflects conflicting attitudes compared to the wider community. Interestingly, previous studies have focused on the attitudes and beliefs irrespective of the type or level of sport played at. This study explored concussion beliefs and attitudes in a cohort of Australian exercise science students, analyzing responses based upon the type and the level of sport participated. Two-hundred and ninety-four students (m = 208; f = 86; age 22 ± 5.2 years) responded to a series of statements regarding their personal attitudes and beliefs towards concussion, risk playing with a concussion, and their views on elite/professional athletes who continue to play after a concussion. Data was compared between the type of sport played (team and individual, contact and non-contact) and the level of sport played at (elite, regional and recreational). Significant differences were reported in those experiencing a concussion, and the number of concussions sustained between different types of sports. Specifically, significant differences in attitudes between team-contact versus individual non-contact sports were found. Similarly, significant differences in attitudes were observed between team contact and individual non-contact sports. Conversely, similar attitudes were found between team contact, team non-contact and individual contact. Irrespective of the level of competition, no differences were found in previous concussion history and the number of concussions, reflecting similar attitudes. The data from this study suggests that concussion awareness programs should be delivered across all sports and to all levels.

A Preliminary Analysis of the Relationship between the Multistage Fitness Test and 300-m Run in Law Enforcement Officers: Implications for Fitness Assessment

Thu, 05 Apr 2018 15:39:30 PDT

International Journal of Exercise Science 11(4): 730-738, 2018. Law enforcement agencies (LEAs) often use fitness tests to assess recruits and incumbents. One fitness test that is gaining popularity is the 20-meter multistage fitness test (20m-MSFT). However, the potential length of this assessment, in addition to the repeated direction changes, means this test may not be appropriate for all officers (e.g. older officers, or those with physical impairments). The 300-m run is shorter, features no direction changes, and could provide an indication of fitness. The study purpose was to investigate the relationship between the 20m-MSFT and 300–m run. Retrospective analysis of data from a convenience sample of 15 incumbents from one LEA were used. Incumbents completed the 20m-MSFT and 300-m run one week apart. Pearson’s correlations (p≤0.05) calculated the relationships between the descriptive data of the incumbents, 20m-MSFT shuttle score and 300-m run time. Linear regression plots were also constructed to determine the predictive relationship between the two assessments. The results indicated a large negative relationship (r=-0.61) between number of shuttles completed on the 20m-MSFT and the 300-m run time. However, there was a low predictive relationship shown by the regression between the 20m-MSFT and 300-m run (R2=0.3728). Although the 300-m run and the 20m-MSFT both provide some measure of general fitness and high-intensity running performance, each assessment generally provides a measure of different physiological qualities. Nonetheless, given the significant correlation between the assessments, the 300-m run could still be a useful assessment for those officers for whom the 20m-MSFT is inappropriate, such as officers with physical limitations.

Lower Extremity Joint Kinematics of Shod, Barefoot and Simulated Barefoot Treadmill Running

Thu, 05 Apr 2018 15:38:49 PDT

International Journal of Exercise Science 11(1): 717-729, 2018. Barefoot running is considered to decrease injury risk, but is not always practical, particularly while running on a fitness center treadmill. The purpose of this study was to compare the kinematics of shod, barefoot, and simulated barefoot running. Twelve subjects (age = 21.1 ± 1.2 years) who regularly run on a treadmill for fitness participated in the study. After a warm up, each runner ran on a Biodex RTM 400 treadmill set at 7.4 mph (approximately 3.3 m/s) in their own shoes, barefoot, and while running “like they were barefoot” in their own shoes. Sixteen reflective markers were affixed to each subject to use PlugInGait (Vicon) to determine three-dimensional body landmark coordinates and to compute lower extremity joint angles. Values at touchdown and during stance were averaged over ten strides for analysis. Repeated measures ANOVA was implemented to determine differences based on running condition (p < 0.05) and post hoc testing was performed with an adjustment for multiple comparisons (p<0.05/3). At touchdown, ankle angle values significantly differed based on condition (6.2 ± 5.9° vs. -4.0 ± 12.0° vs, -0.2 ± 13.3°; p = 0.004 for shod, barefoot and simulated barefoot running, respectively) indicating that when simulating barefoot running the subjects altered their foot strike pattern. Stride frequency differed between shod and barefoot running (1.415±0.068 Hz vs. 1.457±0.065 Hz; p = 0.001) but the simulated barefoot condition did not differ from the shod condition. The runners were able to simulate an important element of barefoot running, but they did not completely mimic their barefoot running pattern.

Stability of Resistance Training Implement alters EMG Activity during the Overhead Press

Wed, 04 Apr 2018 07:35:56 PDT

International Journal of Exercise Science 11(1): 708-716, 2018. Kettlebells often replace dumbbells during common resistance training exercises such as the overhead press. When performing an overhead press, the center of mass of a dumbbell is in line with the glenohumeral joint. In comparison, the center of mass of the kettlebell is posterior to the glenohumeral joint. Posterior displacement of the kettlebell center of mass may result in less stability during the pressing motion. The purpose of this study was to examine muscle activity during an overhead press with resistance training implements of differing stability. Surface electromyography (EMG) for the anterior deltoid and pectoralis major was analyzed for 21 subjects. Technique and pace of the overhead press were standardized and monitored. Filtered EMG data were collected, normalized, and average peak amplitude as a percentage of MVIC was calculated for each repetition. A repeated-measures analysis of variance was used to compare EMG values for the anterior deltoid and pectoralis major across implements. A statistically significant increase in normalized EMG activity (p < .05) was identified in the anterior deltoid when using the dumbbell (63.3±13.3%) compared to the kettlebell (57.9±15.0%). In this study, EMG activity was augmented in the anterior deltoid when using the more stable implement, the dumbbell.

Field Test Performance of Junior Competitive Surf Athletes following a Core Strength Training Program

Tue, 03 Apr 2018 08:53:25 PDT

International Journal of Exercise Science 11(6): 696-707, 2018. Lower body and core muscular strength are essential for optimal performance in many sports and competitive surfers have similar strength demands when maneuvering a surfboard to achieve competition success. Presently, the use of unstable surfaces is excessively utilized by surf coaches and trainers and to date, research does not support this as an effective training method for long-term improvements. Therefore, the purpose of this study was to determine the effectiveness of an 8-week Core Strength Training Program (CSTP) on a battery of field tests specific to assessing core musculature and lower body strength for junior competitive surf athletes. Nineteen American junior competitive surf athletes (age:15.7±1.01yrs, height:1.77±0.007m, mass:64.67±9.08kg) completed pre- and post-tests with a transitional pre-season to in-season 8-week CSTP intervention. The battery of tests included: rotational power (RP), time to peak acceleration (TP), maximal acceleration (Ma), maximal countermovement jump (CMJ), estimated peak power (PP), core strength (CS), core endurance (CE), and rotational flexibility (RF). Means, standard deviations, RMANOVA with a significance level of p < 0.05, and effect sizes were computed. Results demonstrated significant improvements in L.RP, TP, CMJ, PP, CS, and RF. Based on the results, the CSTP is an effective training program for surf coaches and strength and conditioning professionals to improve strength in the core musculature and lower body. In addition, we conclude implementation of the CSTP enhances athletic performance measurements which will likely increase competition success.

Childhood Cancer and Treatment Effects on Motor Performance

Fri, 30 Mar 2018 08:22:15 PDT

International Journal of Exercise Science 11(3): 657-668, 2018. Children with cancer report motor problems several years post treatment. Physical performance limitations can restrict the survivor's ability to participate fully in daily activities necessary for self-care, family life, and/or work. Motor performance in childhood cancer could be an important measure in symptom research. This review addresses motor performance limitations caused by cancer treatment in childhood cancer survivors. Several studies found performance deficits in strength and flexibility. Conflicting research in balance, coordination, and reaction time needs further consideration. The findings may indicate muscle atrophy as a cause of performance limitations rather than neurological issues caused by treatment. The evidence that suggest motor performance is affected by cancer and its treatment is still not fully understood. Larger cohorts of pediatric cancer patients during and after treatment phase are warranted to examine exercise as a preventative measure for deficiencies in motor performance.

A Two-test Protocol for the Precise Determination of the Maximal Lactate Steady State

Tue, 27 Mar 2018 21:26:50 PDT

International Journal of Exercise Science 11(4): 681-695, 2018. The purpose of this study was to determine the efficacy of a two-test method for precisely identifying the Maximal Lactate Steady State (MLSS). Eight male competitive cyclists performed two bouts on a cycle ergometer. Following a maximal oxygen consumption (O2max) test (66.91 ± 5.29 mL∙kg-1∙min-1) we identified the lactate deflection point using the visual deflection (TVis), Log-Log (TLog), Dmax (TDmax), RER = 1.00 (TRER), ventilatory threshold (TVent), and the 1.0 mmol·L-1 increase above baseline (T+1) methods. The second incremental test (SIT) consisted of 6-7 stages (5 min each) starting 20-30 W below to 20-30 W above the predetermined deflection point, in 10 W increments. Comparison of the two tests yielded different threshold estimates (range 11-46W) for all methods (P = 0.001-0.019) except the TLog (P = 0.194) and TRER (P = 0.100). The SIT resulted in significantly (P = 0.007) more narrow range of thresholds (27.5 ± 11.01W) compared to the O2max test (70 ± 42.51W). The TVis from the SIT was identified as the MLSS and was verified using three 45-minute steady-state exercise bouts at 95%, 100%, and 105% of MLSS intensity (average increment 12.8 W). Blood lactate and O2 were recorded every 5 minutes and differed between the three intensities at every time point (P < 0.001). O2 increased from the 5th to the 45th minute by 7.02 mL∙kg-1∙min-1 (100% MLSS), 3.63 mL∙kg-1∙min-1 (95% MLSS) and 7.5 mL∙kg-1∙min-1 (105% MLSS, to the 30th minute). These results indicate that the MLSS was identified correctly by the SIT, the single incremental test overestimated the MLSS intensity, and the TVis provides a very accurate determination of the lactate breakpoint. The use of a second submaximal test is required for a precise identification of MLSS.

The Effects of PCSO-524®, a Patented Marine Oil Lipid derived from the New Zealand Green Lipped Mussel (Perna canaliculus), on Pulmonary and Respiratory Muscle Function in Non-asthmatic Elite Runners

Tue, 27 Mar 2018 17:07:39 PDT

International Journal of Exercise Science 11(3): 669-680, 2018. Habitual endurance training may be associated with mild airway inflammation and subsequent deterioration in lung function. PCSO-524™ (Lyprinol®/Omega-XL®), a supplement extracted from the New Zealand green-lipped mussel (Perna canaliculus), has been shown to moderate airway inflammation in asthmatic subjects. The purpose of this study was to determine whether supplementation with PCSO-524™ improves pulmonary and respiratory muscle function in non-asthmatic elite runners. Sixteen male, non-asthmatic elite runners were randomly assigned to either a treatment (PCSO-524™; 1 capsule contains 50 mg n-3 polyunsaturated fatty acids and 100 mg olive oil, n=8) or placebo (1 capsule contains 150 mg olive oil; n=8) group. During the supplementation period, subjects ingested 8 capsules of either treatment or placebo per day for 12 weeks. Resting pulmonary and respiratory muscle function testing were assessed at baseline and every two weeks throughout the 12 week supplementation period. No significant between- or within-subjects main effects were observed in forced vital capacity, forced expiratory volume in 1-second, forced expiratory flow from 25-75% of lung volume (FEF25-75), peak expiratory flow, maximal voluntary ventilation, maximal inspiratory mouth pressure, and closing volume (p>0.05). A significant within-subjects main effect was observed in maximal expiratory mouth pressure (PEmax) (p=0.024) and lung diffusion capacity (DLCO) (pPEmax and DLCO (p>0.05). A significant treatment by time interaction was observed in FEF25-75 (p=0.026) and DLCO (p=0.024), but no other significant interactions were observed (all p>0.05). Supplementation with PCSO-524™ (Lyprinol®/Omega-XL®) does not improve pulmonary or respiratory muscle function in non-asthmatic elite runners.

The Influence of Body Armor on Balance and Movement Quality

Wed, 14 Mar 2018 08:56:29 PDT

International Journal of Exercise Science 11(1): 648-656, 2018. Body armor is essential to the protection of military personnel; however, body armor may impede the users balance and movement quality. A better understanding of the influence of body armor on balance and movement quality may help in the development of new guidelines for training standards and procedures to mitigate the risk of injury associated with wearing of body armor in warfighters. The purpose of this study was to identify the effects of body armor (combat boots, tactical vest and combat helmet) on balance and movement quality in male military cadets and personnel. Twelve male participants completed the Functional Movement Screen (FMS) and Star Excursion Balance Test (SEBT) under two separate conditions, body armor and non-body armor. Results indicated a significant difference in FMS composite score between the non-body armor and body armor conditions (p =.012), with the non-body armor condition resulting in significantly higher FMS scores than the body armor condition. Additionally, the FMS item score for shoulder mobility was significantly higher (2.25±0.62) in the non-body armor condition than the body armor condition (p= 0.03). The SEBT composite and the three individual reach distances were not significantly different between conditions. Based on the current findings, body armor within a 4.8 kg – 5.3 kg range does appear to impact movement quality as evaluated using the FMS in male military personnel and cadets. More research is needed to determine a threshold of compensatory movement patterns relative to an increase in body armor weight.

Mindfulness and Affective Responses to Treadmill Walking in Individuals with Low Intrinsic Motivation to Exercise

Sun, 04 Mar 2018 07:31:16 PST

International Journal of Exercise Science 11(5): 609-624, 2018. An aversion to the sensations of physical exertion can deter engagement in physical activity. This is due in part to an associative focus in which individuals are attending to uncomfortable interoceptive cues. The purpose of this study was to test the effect of mindfulness on affective valence, ratings of perceived exertion (RPE), and enjoyment during treadmill walking. Participants (N=23; Mage=19.26, SD = 1.14) were only included in the study if they engaged in no more than moderate levels of physical activity and reported low levels of intrinsic motivation. They completed three testing sessions including a habituation session to determine the grade needed to achieve 65% of heart rate reserve (HRR); a control condition in which they walked at 65% of HRR for 10 minutes and an experimental condition during which they listened to a mindfulness track that directed them to attend to the physical sensations of their body in a nonjudgmental manner during the 10-minute walk. ANOVA results showed that in the mindfulness condition, affective valence was significantly more positive (p = .02, np2 = .22), enjoyment and mindfulness of the body were higher (p < .001, np2 = .36 and .40, respectively), attentional focus was more associative (p < .001, np2 =.67) and RPE was minimally lower (p = .06, np2 =.15). Higher mindfulness of the body was moderately associated with higher enjoyment (p < .05, r =.44) in the mindfulness but not the control condition. Results suggest that mindfulness during exercise is associated with more positive affective responses.

Time Course Toward Baseline of Hand-to-Foot BIA Measures Following An Acute Bout of Aerobic Exercise

Thu, 01 Mar 2018 09:03:32 PST

International Journal of Exercise Science 11(2): 640-647, 2018. The purpose of this study was to determine the time course of BIA-derived body fat percentage (BF%) and total body water (TBW) values in the 1 h following a moderate bout (60% heart rate reserve [HRR]) of steady state aerobic exercise in apparently healthy men. College-aged adult males (n=15) had their BF% and TBW estimated via BIA before (PRE), immediately (IP), 10 min (10P), 20 min (20P), 30 min (30P), 40 min (40P), 50 min (50P), and 60 min (60P) post a 30 min bout of moderate treadmill exercise. Exercise intensity was 60% of subjects’ HRR. Compared to PRE values, BIA-derived BF% and TBW were significantly lower and higher, respectively, from IP-30P (all p<0.05). However, BF% and TBW values for 40P-60P were not statistically significant compared to PRE (all p>0.05). The 95% limits of agreement for BF% and TBW were narrowest for IP (±1.5%; ±0.5kg) and widest at 50P (±2.1%; ±0.7kg), respectively. The time periods that produced significantly different BF% and TBW values (i.e., IP, 10P, 20P, and 30P) had smaller 95% limits of agreement than the time periods that produced non-significantly different mean values (i.e., 40P, 50P, and 60P). The 12 h recommendation of avoiding aerobic exercise prior to BIA testing appears to be too stringent. Results from the current study found that BIA-derived BF% and TBW measured at 40P, 50P and 60P were similar to PRE. Furthermore, if BIA is used after aerobic exercise, but prior to 40P, practitioners should consider adjusting for the systematic error (e.g., increase BIA-derived BF% IP by 2.3%).

A Description of Physical Activity Outcomes during Beginning Curling

Wed, 28 Feb 2018 16:41:34 PST

International Journal of Exercise Science 11(6): 633-639, 2018. Identifying and promoting activities which enable participants to meet exercise guidelines is important for promoting a healthy society. The purpose of this study was to describe activity levels of novice participants during participation in the sport of curling. Participants included 29 novice curlers who were either enrolled in a beginning curling class at a local university or novice members in a city-wide curling league. The average exercise duration was 81.3 ± 19.8 minutes and variables monitored included heart rate (HR), steps, and estimated METs. Results indicated an average HR: 106 ± 12 bpm, peak HR: 146 ± 20 bpm, 3114 ± 927 steps, 2.1 ± 0.6 METs. Results indicate light to moderate levels of physical exertion during beginning curling. Moreover, step data indicated that beginning curling made a significant contribution (~30%) toward the 10,000 steps recommended daily.

The Effect of the Menstrual Cycle on the Reliability of Contact-Electrode Bioelectrical Impedance Analyzers

Wed, 28 Feb 2018 11:53:02 PST

International Journal of Exercise Science 11(4): 625-632, 2018. Bioelectrical impedance analysis (BIA) is a noninvasive and relatively inexpensive method of assessing body composition. Manufacturers of BIA technology recommend to avoid testing women when they perceive to be retaining water during the menstrual cycle. The purpose of the present investigation was to examine the effect of the menstrual cycle on body composition determined by contact-electrode BIA analyzers. Forty-three college-aged women volunteered to participate in this study (age=21.2 ± 1.1 years; body mass index = 24.0 ± 3.7 kg/m2). Subjects had their body composition assessed using four different contact-electrode BIA analyzers during the following menstrual cycle phases: menstrual, follicular, early and late luteal. Regardless of the BIA analyzer used for the assessment, no significant differences in body composition measures were found between cycle phases. The results of this study indicate that the contact-electrode BIA devices used in this study can be used at any time during a woman’s menstrual cycle without altering the body composition values.

Evaluating Energy Expenditure Estimated by Wearable Technology During Variable Intensity Activity on Female Collegiate Athletes

Fri, 23 Feb 2018 12:59:24 PST

International Journal of Exercise Science 11(7): 598-608, 2018. Monitoring an athlete’s energy intake and energy expenditure (EE) is an important consideration of nutritional planning for sport conditioning and peak performance. In order to provide appropriate recommendations regarding nutritional requirements and caloric needs, an accurate determination of energy requirements is necessary. By knowing an individual’s EE, a coach, athletic performance staff or trainer can effectively determine training loads and volumes necessary for periodization and seasonal planning for a particular sport. The purpose of this study is to examine the accuracy of the BodyMedia Mini armband while measuring EE in female basketball players during various-intensity game-like conditions. This investigation required three testing sessions: an orientation session, and two randomized experimental trials. Trials included a maximal multistage 20-m shuttle run (Trial I) and 30-minute basketball skills session (Trial II). The independent variable for this investigation was EE estimated by the Mini armband. The dependent variable was EE determined by the Cosmed K4b2 indirect calorimetry (IC) method. EE assessed with the Mini and EE measured with the IC method was significantly correlated for both Trial I (r= 0.839) and Trial II (r= 0.833). EE calculated by the Mini was significantly underestimated in both Trial I (9.41 ± 26.1 total kcals) and Trial II (56.71 ± 14.1 total kcals). During Trial I the underestimation of EE increased with a rise in test level and intensity (p<.05). Due to the underestimation of EE by the Mini, the development of exercise specific algorithms to improve the estimation of EE during intermittent exercise in basketball players is warranted.

Examination of Resistance Settings Based on Body Weight for the 3-Minute All-Out Critical Power Test

Sat, 17 Feb 2018 09:16:07 PST

International Journal of Exercise Science 11(4): 585-597, 2018. There are conflicting suggestions regarding the most valid resistance (3-5% of body weight) to use for the critical power (CP) 3-min all-out (CP3min) test to estimate CP and anaerobic work capacity (AWC). The purpose of this study was to determine if the CP and AWC estimates from the CP3min test were affected by the percentage of body weight used to set the resistance on a Monark cycle ergometer. Ten recreationally trained participants (mean ± SD: Age: 22.2 ± 2.2 yrs.) completed the CP3min test at resistances of 4.5% (CP4.5%) and 3% (CP3%) of body weight to determine the CP and AWC. There were no significant differences between the CP4.5% (167 ± 34 W) and CP3% (156 ± 36 W) estimates. The AWC3% (5.6 ± 2.5 kJ) estimates were significantly lower than the AWC4.5% (9.0 ± 4.0 kJ).The CP and AWC estimates from the CP4.5% were consistent with values reported in the literature, however, the AWC estimate from the CP3% was lower than typically reported. These findings suggested that a resistance set at 3% of body weight for the CP3min test may be too low to accurately estimate AWC, but 3% and 4.5% resulted in the same estimation of CP. Thus, the principal finding of this study was that a resistance of 4.5% of body weight for CP3-min in recreationally trained participants resulted in more accurate estimates of AWC, compared to a resistance of 3%, and supports the use of 4.5% body weight resistance to measure both CP and AWC.

Congruent Accuracy of Wrist-worn Activity Trackers during Controlled and Free-living Conditions

Thu, 15 Feb 2018 13:10:45 PST

International Journal of Exercise Science 11(7): 575-584, 2018. To examine activity tracker accuracy for measuring steps, energy expenditure, and heart rate in controlled and free-living conditions. Forty participants performed four, five-minute stages (walking: 53.7 m∙min-1, 80.5 m∙min-1; running: 134.1 m∙min-1, 160.9 m∙min-1) while wearing the Fitbit Charge HR (FB) and the Mio FUSE (MF) activity trackers. Measurements included steps, energy expenditure (kcals), and heart rate (beats∙min-1). In addition to the FB and MF, participants wore the NL-1000 (NL) activity tracker during waking hours of the subsequent day. One way ANOVAs with Tukey’s post hoc analyses were performed to compare mean values for steps, kcals, and mean heart rate between the FB, MF, and criterion measures. Levels of agreement for heart rate with 95% confidence intervals were examined with Bland-Altman plots. Compared to criterion measures, the FB and MF underestimated steps and overestimated kcals at 53.7 m∙min-1 (FB: 12.7% for steps, 89.2% for kcals; MF: 15.8% for steps, 44.9% for kcals, p<.001) and 80.5 m∙min-1 (FB: 9.7% for steps, 69.9% for kcals; MF: 13.4% for steps, 32.0% for kcals, p<.001). During free-living conditions, the MF significantly underestimated steps by 30.0% (p<.05). Increasing exercise intensity is indicative of heightened accuracy for step detection and kcal estimation for the FB and MF, while decreasing heart rate accuracy for the FB. However, the MF performed poorly for estimating total daily activity.

Behavior Change Techniques and Physical Activity Using the Fitbit Flex®

Thu, 15 Feb 2018 09:08:22 PST

International Journal of Exercise Science 11(7): 561-574, 2018. Due to the availability of low-cost accelerometers, there has been an increase in the adoption of physical activity monitors (e.g., Fitbit®) (14) accompanied by a desire to understand the behavior change techniques (BCTs; 15) present in such monitors. One specific Fitbit® monitor incorporates 20 BCTs (15), but how users experience these BCTs has yet to be explored. The purpose of this study was to explore user’s experience with the Fitbit Flex® regarding physical activity behavior and BCTs. The specific research objectives were to: 1) describe Fitbit Flex® users and 2) explore user’s engagement with the 20 BCTs. Participants (n=28) completed an online survey composed of questions about demographics, step volume, and perceived importance and/or frequency of use of the BCTs. Participants were mostly female (82.1%), between the ages of 18-71 years, and had used the Fitbit® for an average of 5 months. There was a significant increase of almost 2000 steps per day (p=0.003) from participants’ first week to their past week (i.e., last 7 days) of monitor use. The BCTs rated among the highest for perceived importance for physical activity behavior (i.e., step volume) were “feedback on behavior”, “self-monitoring of behavior”, and “goal setting (behavior)”. In brief, Fitbit® devices have the potential for increased step-based physical activity. As well, the present study contributes to understanding how user’s experience BCTs in the Fitbit Flex® which can inform future physical activity promotion and interventions.

Validation of PiezoRx Pedometer Derived Sedentary Time

Wed, 14 Feb 2018 23:22:36 PST

International Journal of Exercise Science 11(7): 552-560, 2018. Although pedometers are valid tools for measuring physical activity, to date they have not been used to assess sedentary time. The primary purpose of this study was to determine if the PiezoRx pedometer is a valid and reliable measure of sedentary time compared to the hip-worn Actical accelerometer. A secondary purpose was to compare sedentary time derived via the Fitbit Flex with that of the Actical. Finally, a third purpose was to compare sedentary time derived from the above devices, with that of the ActivPAL inclinometer. Thirty-five participants ages 11-69 years (Mage= 23.3; 21 Female) wore five devices for up to one week: two PiezoRx pedometers, an Actical, an ActivPAL and a Fitbit Flex. Participants recorded daily wear-time of each device using a log sheet. The average sedentary time calculated from the PiezoRx (716±137.68 min/day) was not different from the Actical (694 ±136.11 min/day, p>0.05), although it was higher than the ActivPAL (475±171.52 min/day) and Fitbit Flex (530±149.94 min/day, all p<0.001). Sedentary time from all devices were significantly correlated with each other, with the strongest relationship seen between the Actical and PiezoRx (R2=0.93, p<0.001). In comparison to the ActivPAL, error in PiezoRx- (R2=0.96), Actical- (R2=0.96) and Fitbit Flex- (R2=0.34) determined sedentary time was strongly associated with standing time (all p<0.001). Sedentary time derived using the PiezoRx pedometer may be statistically equivalent to the Actical accelerometer, but not the ActivPAL inclinometer or Fitbit Flex.