Effects of Different Surfaces on Metabolic Cost During Repetitive Jumping: A Pilot Study.

The purpose of this pilot study was to determine if there is a difference in metabolic cost when jumping on platforms of varying thickness, as well as whether a difference exists in metabolic cost between genders exists on the different platforms. Fourteen participants (seven males and seven females) completed three repetitive jumping trials on the DigiJump machine. Each trial was performed at a cadence of 120 jumps per minute and at a minimum height of 1/2″ per jump. Trials were completed on platforms of 1/2″, 3/8″, and 1/4″ thickness. Participants were instructed to jump as long as possible while maintaining the prescribed cadence or until fifteen minutes had elapsed. There were no differences observed in metabolic cost or exertion for all participants or between genders as indicated by oxygen consumption, respiratory exchange ratio, upper leg RPE, or lower leg RPE. There were also no differences for durations of exercise the participants were able to sustain on the machine. However, when comparing data between genders, a significant interaction was observed in total body RPE across the three platforms (p = .009) and in HR on the 1/2″ platform (p = .018). Results from this study indicate that metabolic cost is similar during repetitive jumping regardless of platform rigidity or gender. However, post-trial comments from participants did show preferences towards specific platforms, though this was not apparent in exercise duration.

IJES Self-Study on Participants' Sex in Exercise Science: Sex-Data Gap and Corresponding Author Survey.

A sex-data gap exists between females and males within the sport and exercise science literature, and implications are far-reaching. The purpose of this work was to (a) heed recent calls and scrutinize data from within IJES to address the gap and (b) gain insight on self-identified sex of IJES corresponding authors. The present self-study included all published manuscripts from 2008 through 2021. A total of 851 publications were included, and 806 (94.7%) reported data on participant sex. There was a difference between publications that included only females (n = 132) versus only males (n = 215), and three publications reported data on sex according to non-binary identifications (0.4%). There was an overall difference between the number of female (n = 54,153; 35.9%) and male (n = 96,890; 64.1%) participants. To gain insight on self-identified sex of corresponding authors, we performed an IRB-approved research study. Among 761 unique corresponding authors, 168 individuals provided 157 usable responses-58 biological females (36.9%) and 99 biological males (63.1%). We fully support the prerogative of researchers to ethically conduct investigations and encourage open-mindedness and inclusion in future research. With data revealing an approximate one-third female (36%) and two-thirds male (64%) composition, and corresponding author feedback on self-identified sex being similar (36.9% and 63.1%, respectively), we propose a new concept that should be analyzed: is the sex-data gap representative of the composition of the field? We are not excusing the sex-data gap issue as if it cannot be addressed, and we urge others to join us in researching this line of inquiry.

A VO2max Protocol for Young, Apparently Healthy Adults.

The Bruce and Astrand treadmill protocols are commonly utilized when assessing maximal oxygen consumption (VO2max). However, the steep grade implemented in the protocols often leads to localized muscular fatigue, potentially causing participants prematurely to terminate the test prior to reaching their true VO2max. The purpose of this study was to evaluate a Novel VO2max protocol that may be better suited for young, apparently healthy populations. The Novel protocol starts at a higher speed and lower initial grade to limit lower extremity fatigue. Fifteen participants performed the Bruce, Astrand, and Novel protocols with the following maximal values recorded from each: VO2max, maximal ventilation (VEmax), respiratory exchange ratio (RER), heart rate (HR), rating of perceived exertion (RPE) and time to exhaustion (TTE). The Novel protocol displayed substantial agreement with both criterion protocols. Mean absolute percent error (MAPE) was less than 10% indicating that the Novel protocol is a valid measurement for VO2max values. Bland-Altman analysis revealed that the Novel protocol exhibited a low degree of bias, with tight limits of agreement when compared to the Bruce (bias ±95% LOA = 0.824 ± 3.163) and Astrand protocols (-0.153 ± 3.528) for VO2max. A paired samples t-test revealed no significant differences between Novel and criterion protocols for VO2max. Paired samples t-tests revealed that the Novel protocol had significantly lower TTE when compared to the Bruce and Astrand protocols and produced similar VO2max values to that of the Bruce and Astrand. The Novel protocol may be considered a valid and time-efficient protocol.

Effects of Varying Load Intensity on Skeletal Muscle Damage Between Two Isovolumic Resistance Exercise Bouts.

There are limited data comparing the efficacy of resistance loads within the hypertrophy range for promoting muscular growth, particularly when similar training volumes are utilized. The purpose of this study was to determine if two similar volume-loads, utilizing different intensities, would produce dissimilar muscular damage and inflammation. Eleven resistance-trained, college-aged males participated in this study. After testing 1RM barbell squats, participants completed two similar volume-load barbell squat sessions at two different resistance loads (67% and 85% of 1RM) on two separate visits. Venous blood samples were collected at baseline and one hour after completion of each exercise session. Plasma was isolated and analyzed for myoglobin and C-reactive protein (CRP) expression via ELISA. Plasma myoglobin expression was significantly elevated above baseline (BASE) values only after the 85% of 1RM (HHL) session (p =0.031), though the 67% (LHL) trial (p = 0.054; η2 = 0.647) was approaching significance (BASE: 1.42±.12 ng/mL; LHL: 4.65±1.13 ng/mL; HHL: 5.00±1.01 ng/mL). No changes in plasma CRP were observed. Despite attempts to equate volumes between resistances, mean total volume-load was significantly higher during the 67% of 1RM trial than during the 85% trial. Resistance loads at 85% of 1RM inflict significantly increased muscle damage over baseline values, even when significantly less total volume was lifted during the 85% trial. Individuals looking to maximize strength and hypertrophy during general training or during rehabilitation may benefit from these findings when determining the appropriate training load.

New Author Guidelines in Statistical Reporting: Embracing an Era Beyond p < .05.

Statistical reporting of quantitative research data has been plagued by potential bias and reporting suppression due to a single numerical output: the p-value. While there is great importance in its merit, creating a pass-fail system (set at point of .05) has created a culture of researchers submitting their project's data to a filing cabinet if it does not yield "statistical significance" based on this value. The editors of the International Journal of Exercise Science are following the American Statistical Association's call for statistical reform by adjusting our reporting guidelines to the following requirements: [1.] make an intentional effort to move away from statements "statistically significant" or "not significant;" [2] all p-values are to be reported in their raw, continuous form; [3.] measures of the magnitude of effect must be presented with all p-values; [4.] either an a-priori power analysis with relevant citations should be included or post-hoc power calculations should accompany p-values and measures of effect. The ultimate goal of this editorial is to join with other scholars to push the field toward transparency in reporting and critical, thoughtful evaluation of research.

Evaluation of Repetitive Jumping Intensity on the Digi-Jump Machine.

Cardiorespiratory endurance is an important element of aerobic fitness, particularly in weight management and reducing risk for cardiovascular disease. While there are numerous options for aerobic exercise, rope jumping is often overlooked. In addition to regular exercise and a healthy diet, the American Heart Association strongly recommends rope jumping. The first purpose of this study was to determine the steady state metabolic cost of repetitive jumping on the Digi-Jump machine to evaluate whether exercise on this device is more or less strenuous than similar exercise with a jump rope, as demonstrated in previous literature. A second purpose was to determine the relative intensity of exercise on the Digi-Jump by comparing to VO2max as measured on a treadmill. Twenty-seven participants completed two trials, one jumping trial at a rate of 120 jumps per minute with the jumping height set at 0.5 inch for 5-min on the Digi-Jump, and one graded exercise test using the Bruce protocol. Oxygen uptake (VO2), heart rate (HR), respiratory exchange ratio (RER), and rating of perceived exertion (RPE) were measured each minute during each trial. Results of this study indicated that steady state VO2 during the 5-min jump test was reached at the 3rd min. Steady state variables during the jumping trial expressed as percentage of max were as follows: VO2 was 57.1% of VO2max; HR was 80.9% of HRmax; RER was 86%of RERmax; and RPE was 75.2% of RPEmax. These data indicate that repetitive jumping is a strenuous activity and similar in intensity to jumping rope, even if the trial is done on the Digi-Jump machine with free-swinging arms and without a jump rope.

Post Exercise Hypotension Following Concurrent Exercise: Does Order of Exercise Modality Matter?

Cardiovascular (CV) and resistance training (RT) can moderate negative effects of aging, disease, and inactivity. Post-exercise hypotension (PEH) has been used as a non-pharmacological means to control and reduce BP. Few have evaluated PEH response following a bout of exercise combining CV and RT, whether or not there is an order effect, or if PEH continues when activities of daily living (ADLs) are resumed. Participants (N = 10) completed a non-exercise control, a graded exercise test (GXT), and two concurrent sessions (CVRT and RTCV). Each session was followed by a 60-minute laboratory and 3-hour ADLs PEH assessment, respectively. Two-way and Welch-one-way repeated measures ANOVAs were used to determine differences between among conditions in PEH. There was a significant interaction between BP and condition following the 60-minute laboratory measure (p = .030, ηp 2 = .166) and the ADLs BP assessments (p = .008, ηp 2 = .993), respectively. PEH occurred following concurrent exercise conditions at minute 45 for RTCV (118 ± 8, p = .041; 95% CI [0.223, 17.443]) and minutes 50 (117 ± 9; p = .036 95% CI [0.441, 21.097]) and 55 (118 + 8; p < .001; 95% CI [5.884, 14.731]) following CVRT. BP was elevated during ADLs following the control session compared to the GXT, RTCV, and CVRT. Regardless of the order, concurrent exercise is effective in potentiating PEH. Elevation in BP associated with ADLs can be mitigated if exercise is performed previously.

Ethical Issues Relating to Scientific Discovery in Exercise Science.

This work aims to present concepts related to ethical issues in conducting and reporting scientific research in a clear and straightforward manner. Considerations around research design including authorship, sound research practices, non-discrimination in subject recruitment, objectivity, respect for intellectual property, and financial interests are detailed. Further, concepts relating to the conducting of research including the competency of the researcher, conflicts of interest, accurately representing data, and ethical practices in human and animal research are presented. Attention pertaining to the dissemination of research including plagiarism, duplicate submission, redundant publication, and figure manipulation is offered. Other considerations including responsible mentoring, respect for colleagues, and social responsibility are set forth. The International Journal of Exercise Science will now require a statement in all subsequent published manuscripts that the authors have complied with each of the ethics statements contained in this work.

From the Editors: A Guide for Peer Review in the Field of Exercise Science.

Since its inception, the mission of the International Journal of Exercise Science (IJES) has been to engage student researchers, to provide an outlet for peer-review and possible publication of their work, and to grant an opportunity for them to gain experience as peer-reviewers. The Editors of IJES take pride in providing these opportunities for student involvement, and we are constantly seeking new and innovative ways to enhance students' professional development. As our readership has expanded across the globe and our scope has broadened to cross many Kinesiology related disciplines, we believe it is timely to revisit the purpose of peer-review, give advice on best practices, and provide a template for reviews. Presenting these guiding principles should simplify and streamline both the review and the revision processes for students and professionals alike.

Caffeine affects CD8+ lymphocyte apoptosis and migration differently in naïve and familiar individuals following moderate intensity exercise.

The purpose of this investigation was to determine the lymphocyte subset response to 30 min of moderate treadmill exercise during caffeine supplemented (6.0 mg.kg(-1)) and placebo conditions in caffeine-naïve and -familiar individuals. Seventeen individuals participated (caffeine-familiar = 8, caffeine-naïve = 9) completing two exercise bouts (caffeine supplemented and placebo control) 48 h apart in a counterbalanced and double-blinded fashion. Individuals were classified as follows: caffeine-naive <50 mg.d(-1) and caffeine-familiar >200 mg.d(-1) Whole blood samples were obtained at rest, 30 min after caffeine or placebo ingestion, immediately following exercise, and 1 h post exercise. Blood was used to analyze apoptosis (annexin V) and cellular migration (CX3CR1) responses in lymphocyte subsets (CD4+, CD8+, CD19+). Absolute changes from rest values were calculated and differences between conditions were determined through Chi-squared analysis with significance accepted at P <0.05. With regard to CD4+ and CD19+ lymphocytes, the interaction of caffeine and exercise did not affect naïve individuals to a greater extent immediately post exercise when compared to familiar, as similar apoptotic and migratory responses were observed (P >0.05). However, CD8+ lymphocyte cell death and migration responses were observed to be significantly greater at each sampling point in caffeine-familiar individuals (P <0.05). It is possible that chronic caffeine supplementation may prime CD8+ cell receptors for responsiveness to apoptosis and migration and the consequence of this form of immunosuppression in the post-exercise period should be determined.

Repeated high-intensity Wingate cycle bouts influence markers of lymphocyte migration but not apoptosis.

Studies have shown significant changes in lymphocytes during continuous exercise, but little has been shown on the effect of repeated high intensity bouts. This study was designed to examine the effect of repeated intermittent bouts on lymphocyte subset cell count, apoptosis, and migration. A series of 6 Wingate anaerobic cycle tests were performed by participants (N = 8) with blood samples attained before, immediately following, and after a designated recovery period (excess postexercise oxygen consumption (EPOC)) to observe lymphocyte changes. Lymphocyte subsets (CD4+, CD4/CD45RA+, CD8+, CD8+/CD45RA+, CD19+) were assessed for apoptosis (annexin V+) and cellular migration (CX(3)CR1). Our results indicate that the CD8+ and CD8+/CD45RA+ subsets were significantly influenced by the repetitive Wingate cycling protocol such that cell counts increased with exercise, and then decreased at EPOC termination (p = 0.016). The observed postexercise decrease in CD8+ and CD8+/CD45RA+ cells was accompanied by a significant change in the CX(3)CR1 cell migration receptor (p = 0.019), but not apoptosis (p = 0.87). This indicates that with repetitive high-intensity cycling, the response in CD8+ cells following the bout is likely due to cell migration rather than cell death.

Student peer review decisions on submitted manuscripts are as stringent as faculty peer reviewers.

The International Journal of Exercise Science is the only student-centered peer-reviewed journal in its field. Upon graduate student first author submissions, two student reviewers and one faculty reviewer are asked to review. On professionally submitted papers, two faculty peers are asked to assess the manuscript. The purpose of the present study was to determine whether graduate students returned similar decisions compared with faculty reviewers who evaluated the same manuscript. In addition, decisions of faculty peers reviewing graduate student- versus faculty-submitted manuscripts were compared. Mean comparisons between groups were evaluated using independent t-tests with significance at P ≤ 0.05. Graduate students (2.21 ± 0.69) and faculty peers (2.24 ± 0.66) returned similar decisions on student-submitted manuscripts (P = 0.84). Faculty decisions on manuscripts submitted by a professional primary author (1.86 ± 0.77) were not different compared with faculty peers reviewing student manuscripts (P = 0.06). Statistics revealed that graduate students are just as stringent in the peer review process as established reviewers. Additionally, faculty reviewers evaluated manuscripts equally regardless of submission type.

Exercise-induced immune cell apoptosis: image-based model for morphological assessment.

Methods of assessing exercise-induced lymphocyte apoptosis have produced varying results. While morphological methods generally yield a significantly greater apoptotic index compared to those employing biochemical markers, benefits and limitations are associated with each methodology. Of interest in this report is the limitation of subjectivity associated with the morphological technique. To overcome the lack of objectivity associated with the morphological method, we describe an image-based approach by which computer software assesses the characteristics associated with lymphocyte apoptosis. A stochastic controlled deformable model can be employed to detect the classic morphological apoptotic changes induced by exercise, including membrane blebbing and the formation of apoptotic bodies. We propose that an objective evaluation of multiple points in the apoptotic process through the proposed model in conjunction with current biomarker methods has the potential to advance our understanding of the exercise-induced immune cell death response to a greater degree than current methods.

From the Editors: Assessing the International Journal of Exercise Science after Two Years.

The popularity of the International Journal of Exercise Science continues to rise. As a student-focused journal, we are pleased to provide these future professionals with opportunities to gain experience with the peer review process, both through submitting their original work and as manuscript reviewers. Our editorial process is changing as section editors with specialties within the field of exercise science have agreed to take on these responsibilities. In addition, we are proud to also publish conference proceedings from various meetings held around the world. A list of individuals who have reviewed manuscripts throughout the last year is included.

From the Editors: Assessing the International Journal of Exercise Science after One Year.

Western Kentucky University (WKU) strives to be a "leading American university with international reach." In an effort to contribute to that mission, Drs. Scott Lyons and James Navalta of the Exercise Science program endeavored in 2007 to start a student-focused, on-line journal. Working closely with Berkeley Press, the platform for the International Journal of Exercise Science (IJES) was established during the summer of 2007 and it went "live" in January 2008. The journal has now been on-line for over one year and has enjoyed great success, with quality research submitted from graduate and undergraduate students, as well as professionals. We at IJES look forward to continued success in 2009.

Test-Retest Reliability of the Digijump Machine.

Repetitive jumping has been identified as a possible exercise modality able to provide sufficient stimulus to improve bone health. However, it is necessary to establish whether repetitive jumping can elicit a consistent physiological response with the ablity to monitor work rate. The purpose of this investigation was to determine the stability reliability of the Digijump device for the commonly used laboratory measures of oxygen uptake (VO2), heart rate (HR), and rate of perceived exertion (RPE). College-aged individuals (N = 17) completed two 3-min repetitive jumping bouts on the Digijump machine (120 jumps per minute, jump height = 1.27 cm) at least seven days apart. Stability reliability was calculated using the intraclass correlation coefficient derived from 1-way ANOVA. Absolute VO2 displayed the highest test-retest reliability (0.95), while the coefficient for relative VO2 was also acceptable (0.71). The test-retest reliability coefficients for HR (0.89), and RPE (0.75) were determined to be within acceptable limits. Coefficients for all variables compared well with the stability reliability reported for other ergometers such as the Stairmaster, treadmill, and cycle. This data represent an important step in determining the validity of the Digijump machine for physiological testing.