Mark A. Schafer’s research while affiliated with Western Kentucky University and other places

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Publications (18)


The Validity of Perceptual Recovery Status on Monitoring Recovery During a High-Intensity Back-Squat Session
  • Article

December 2023

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51 Reads

International Journal of Sports Physiology and Performance

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Whitley J. Stone

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Adaptations to resistance training and subsequent performance can be undermined by inadequate interset recovery. Methods typically used to monitor recovery were developed for longitudinal use, making them time-inefficient within singular exercise bouts. If valid, perceptual recovery status (PRS) may be used as an efficient and inexpensive assessment tool to monitor individual recovery. Purpose : The aim of this study was to assess the validity of PRS on monitoring recovery during a high-intensity back-squat session. Methods : Ten healthy men participated in the 2-session study (separated by at least 48 h). Session 1 included anthropometrics, PRS familiarization, and a 1-repetition-maximum back squat. Session 2 included a high-intensity protocol (5 sets of 5 repetitions; 5-min interset recovery; 85% of 1-repetition maximum). PRS was obtained before the first set and during the last 30 seconds of each 5-minute recovery; rating of perceived exertion (RPE) was also collected. A linear position transducer collected mean barbell velocity (MBV). Repeated-measures correlations assessed the common intraindividual relationships of PRS scores to intraset MBV and RPE, respectively. Results : A very large, positive correlation appeared between PRS and MBV ( r [95% CI] = .778 [.613 to .878]; P < .0001). A large, negative correlation emerged between PRS and RPE ( r [95% CI] = −.549 [−.737 to −.282]; P < .001). Conclusions : Results indicate that PRS can be a means for practitioners to monitor individualized recovery. PRS tracked well with RPE, strengthening its utility in a practitioner-based setting. Findings provide insight into the practicality of PRS for recovery monitoring. It could be used alongside other measures (eg, MBV and countermovement jump) to individually program and maintain performance.


McNemar's Test for attainment of maximal criteria between Novel and Criterion protocols (n = 15).
A VO2max Protocol for Young, Apparently Healthy Adults
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  • Full-text available

October 2023

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94 Reads

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.

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Impact of 10-Week Evidence-Based Falls Prevention Program on Outcomes Related to Falls Risk in Community-Dwelling Older Adults

August 2023

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23 Reads

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1 Citation

This quasi-experimental study evaluated the impact of a 10-week evidence-based falls prevention program (Bingocize®) on self-reported fear of falling, general health, physical activity, social isolation, and avoidance behavior, in community-dwelling older adults in Virginia. Participants > 60 years of age (n= 481) attended BingocizeR group sessions twice per week for 10 weeks. The program combined conventional bingo with periodic strength, balance, flexibility exercises, and fall prevention education. Pre and post assessments gauged participants' self-perception of fear of falling, general health, physical activity, social isolation, and avoidance behavior. 481 participants attended at least 80% of the sessions. Following the intervention, paired sample t-tests revealed statistically significant improvements (p <.05) in fear of falling, physical activity, social isolation, avoidance behavior, and yet there was no notable change in self-reported general health. The 10-week BingocizeR program appears to improve physical activity, social isolation, avoidance behavior, and fear of falling. Self-reported general health did not significantly change.



Figure 1. Physical activity levels in pregnancies complicated by FGR. Note: 1st, 2nd, and 3rd trimester timepoints on the graph represent the middle of each trimester. * p < 0.05, difference in PA level from recommended level (150 min/week); ∆ < 0.05, change in PA from one timepoint to the next; ···· denotes recommended amount of physical activity before and during pregnancy (150 min/week); ----denotes mean timepoint of FGR diagnosis (25.5 ± 5.9 weeks gestation).
Figure 2. Summary of content analysis findings highlighting physical activity fears and healthcare provider advice for physical activity before and after FGR diagnosis. Nonbold text and percentages refer to respondents among those who indicated 'yes' to the variable (i.e., fears and receiving advice) and provided an example. FGR-fetal growth restriction; PA-physical activity; bold text and percentages refer to full sample. This figure was created with BioRender.com (accessed on 8 April 2022).
Demographic characteristics.
List of pregnancy and fetal complications in conjunction with FGR.
To Be Active or to Stop? A Cross-Sectional Retrospective Study Exploring Provider Advice and Patient Fears Surrounding Physical Activity in Pregnancies Complicated by Fetal Growth Restriction

May 2022

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75 Reads

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1 Citation

Exercise guidance for women with pregnancies complicated by fetal growth restriction (FGR) is vague, despite the fact that physical activity during pregnancy improves placental development, placental blood flow, and encourages healthy fetal growth. The goal of this study is to test the hypothesis that women with pregnancies complicated by FGR are fearful of physical activity and are being given unclear or limited advice from healthcare providers. Participants (N = 78) (women who delivered an infant diagnosed with FGR within the past 5 years) took an electronic survey including demographic information, pregnancy information, provider advice recall, and other health-related information relevant to growth-restricted pregnancies. Quantitative and qualitative (post-positivism paradigm) methods were employed to analyze the data. When asked specifically about how the FGR diagnosis impacted their activity levels, nearly 50% of participants said the diagnosis led them to decrease their activity levels. Participants reported that healthcare providers who do discuss activity with pregnant patients with FGR suggest low-intensity activities or ceasing activity, although the majority of providers did not discuss activity at all. More fears surrounding physical activity were reported post-FGR diagnosis, including worrying about fetal growth and development and causing fetal harm when engaging in physical activity.


Participants' descriptive statistics.
Evaluation of Repetitive Jumping Intensity on the Digi-Jump Machine

August 2020

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69 Reads

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5 Citations

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?

February 2020

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91 Reads

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4 Citations

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, ηp2 = .166) and the ADLs BP assessments (p = .008, ηp2 = .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.


Participant Demographics.
Intervention Effects.
Effects of a Game-Centered Health Promotion Program on Fall Risk, Health Knowledge, and Quality of Life in Community-Dwelling Older Adults

November 2019

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91 Reads

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5 Citations

Quality of life (QOL) is an important aspect of overall well-being in older adults and can be improved with increased physical activity. One in four older adults experiences a fall each year, making it necessary to focus public health interventions towards decreasing fall risk and improving QOL in older adults. The purpose of this study was to determine the effects of the health promotion program, Bingocize®, on QOL and fall risk in community-dwelling older adults (n = 36; mean age 73.63 ± 6.97). Participants were clustered and randomly assigned to (a) experimental (n = 19; participating in Bingocize® program, or (b) control (n = 17; only played normal bingo). Each group completed a 12-week intervention that consisted of two 45-60 minute sessions per week. There were no significant interactions for any of the variables, with the exception of positive affect (PA) (F (1,34) = 5.66, p = 0.02, η p 2 = 0.15 , power = 0.64) and handgrip strength (F (1,34) = 8.31, p = 0.007, η p 2 = 0.196 , power = 0.80). There was also a significant main effect for time for health knowledge. Participating in the Bingocize® health promotion program can produce a meaningful and detectable change in handgrip strength and PA in community-dwelling older adults.



Citations (8)


... Nonetheless, there was probably an insufficient time period (i.e., six weeks) to induce detectable hypertrophy in the studies providing data for muscle mass after PJT that were included in our meta-analysis [112]. For adipose markers, a relatively high jumping rate (e.g., 100 per minute) with reduced, or no, inter-repetition rest, can increase cardiorespiratory responses [113,114], and, thus energy expenditure and so, potentially, contributes to reduced fat mass [115]. However, in the studies analyzed in the current metaanalysis, traditional PJT interventions were incorporated, usually involving a lower amount of total energy expenditure [28,37,46]. ...

Reference:

A Systematic Review with Meta-Analysis on the Effects of Plyometric-Jump Training on the Physical Fitness of Combat Sport Athletes
Evaluation of Repetitive Jumping Intensity on the Digi-Jump Machine

... Following a healthy lifestyle by exercising is one of the most important treatments recommended for prehypertension (Zeigler, Z. (2016) (17).Regular exercise helps reduce blood pressure, whether it is aerobic, resistance, or concurrent exercises , A healthy lifestyle and regular physical activity are also considered a less expensive and safer option, with no negative effects associated with blood vessels (Pescatello, L. (2004) (9). The use of concurrent exercise sessions has an functional effect on postexercise hypotension (PEH) , when acute exercise is used regardless of exercise order (Stone, W. J., (2020) (13). In this study we are looking The effect of concurrent exercise difference order on postexercise hypotension using chronic exercise. ...

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

... Bingocize ® is an example of one EBFP available to organizations to help address the growing problem of falls. Bingocize ® strategically combines the familiar game of bingo, falls prevention education, and exercise (9,10). Participants complete a series of strategically inserted exercises designed to increase or decrease the intensity and volume of exercise (10). ...

Effects of a Game-Centered Health Promotion Program on Fall Risk, Health Knowledge, and Quality of Life in Community-Dwelling Older Adults

... The body experiences dramatic physiological and psychological changes during pregnancy. This is natural as exercise helps the body to remain healthy (Perales et al., 2016;Gregg & Ferguson, 2017;Schafer et al., 2019). Pregnant women must indulge in regular physical activities called "prenatal exercise" (Fraser and Cooper, 2014). ...

Evidence-based Educational Brochures Influenced Beliefs And Improved Knowledge Regarding The Benefits Of Exercise During Pregnancy: 3109 Board #155 May 31 2:00 PM - 3:30 PM
  • Citing Article
  • June 2019

Medicine and Science in Sports and Exercise

... This included 18 studies that measured total activity energy expenditure of athletes performing their usual training program that included resistance training. Monitors used were the Sensewear armband (n = 10) [1,46,51,53,71,79,80,109,157,185], chest-mounted heart rate monitor (n = 5) [98,117,155,156,177], accelerometer (n = 5; wrist-mounted, n = 3; hip-mounted, n = 1; or waist-mounted, n = 1) [140,147,162,163,192], combination heart rate and accelerometer (n = 7; chest-mounted, n = 5; wrist-and chest-mounted, n = 1; or wrist-mounted, n = 1) [115,129,165,167,186,190] and multiple wearable sensors (n = 4; wrist-and chest-mounted, n = 2; wrist-mounted, n = 1; and wrist-, hip-and waistmounted, n = 1) [25, 57,96,131,196] ...

Validity of Activity Trackers in Estimating Energy Expenditure During High-Intensity Functional Training
  • Citing Article
  • May 2019

... For example, in the USA, the median range to complete PhD is 6-12 years, depending on the discipline (National Center for Science and Engineering Statistics, 2021), while the dropout rate is estimated at a disturbing 50% (Cassuto, 2013). Success factors are often related to navigating the dissertation process (Young et al., 2019), and the so-called "departmental culture," including student/faculty relationship, student satisfaction with the program, student-to-student interactions (Bair and Haworth, 2005), including peer mentorship (Preston et al., 2014). The problem with navigating "departmental culture" exacerbates in interdisciplinary PhD programs (such as those that involve faculty from multiple departments, as in the case of iSchools), because students have to "span boundaries between areas, departments, and knowledge bases" (Gardner et al., 2011). ...

Factors Affecting PhD Student Success

... Cunningham, Simmons, and Mascarenhas 2018), as well as recruitment and retention (e.g. Fowler et al. 2019;Hall et al. 2018;Livingston and Forbes 2016). We make the case that research related to behaviours and biophysical traits that are most obviously seen have grown in size and sophistication in ways that are connected with attempts to modernize officiating (i.e. ...

Evaluation Of The Health And Physical Fitness And Factors Influencing Retention Of Scholastic Sports Officials In The Sport Of American Football: 782 Board #43 May 30 2
  • Citing Article
  • May 2018

Medicine and Science in Sports and Exercise