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Dive into the research topics where Len Kravitz is active.

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Featured researches published by Len Kravitz.


Journal of Investigative Medicine | 2013

Mind-Body Practices for Posttraumatic Stress Disorder

Sang Hwan Kim; Suzanne M. Schneider; Len Kravitz; Christine M. Mermier; Mark R. Burge

Background Mind-body practices are increasingly used to provide stress reduction for posttraumatic stress disorder (PTSD). Mind-body practice encompasses activities with the intent to use the mind to impact physical functioning and improve health. Methods This is a literature review using PubMed, PsycINFO, and Published International Literature on Traumatic Stress to identify the effects of mind-body intervention modalities, such as yoga, tai chi, qigong, mindfulness-based stress reduction, meditation, and deep breathing, as interventions for PTSD. Results The literature search identified 92 articles, only 16 of which were suitable for inclusion in this review. We reviewed only original, full text articles that met the inclusion criteria. Most of the studies have small sample size, but findings from the 16 publications reviewed here suggest that mind-body practices are associated with positive impacts on PTSD symptoms. Mind-body practices incorporate numerous therapeutic effects on stress responses, including reductions in anxiety, depression, and anger, and increases in pain tolerance, self-esteem, energy levels, ability to relax, and ability to cope with stressful situations. In general, mind-body practices were found to be a viable intervention to improve the constellation of PTSD symptoms such as intrusive memories, avoidance, and increased emotional arousal. Conclusions Mind-body practices are increasingly used in the treatment of PTSD and are associated with positive impacts on stress-induced illnesses such as depression and PTSD in most existing studies. Knowledge about the diverse modalities of mind-body practices may provide clinicians and patients with the opportunity to explore an individualized and effective treatment plan enhanced by mind-body interventions as part of ongoing self-care.


The Journal of Clinical Endocrinology and Metabolism | 2013

PTSD symptom reduction with mindfulness-based stretching and deep breathing exercise: randomized controlled clinical trial of efficacy.

Sang Hwan Kim; Suzanne M. Schneider; Margaret Bevans; Len Kravitz; Christine M. Mermier; Clifford Qualls; Mark R. Burge

CONTEXT Abnormal cortisol levels are a key pathophysiological indicator of post-traumatic stress disorder (PTSD). Endogenous normalization of cortisol concentration through exercise may be associated with PTSD symptom reduction. OBJECTIVE The aim of the study was to determine whether mindfulness-based stretching and deep breathing exercise (MBX) normalizes cortisol levels and reduces PTSD symptom severity among individuals with subclinical features of PTSD. DESIGN AND SETTING A randomized controlled trial was conducted at the University of New Mexico Health Sciences Center. PARTICIPANTS Twenty-nine nurses (28 female) aged 45-66 years participated in the study. INTERVENTION Sixty-minute MBX sessions were conducted semiweekly for 8 weeks. MAIN OUTCOME MEASURES Serum cortisol was measured, and the PTSD Checklist-Civilian version (PCL-C) was performed at baseline and weeks 4, 8, and 16. RESULTS Twenty-nine participants completed the study procedures, 22 (79%) with PTSD symptoms (MBX, n = 11; control, n = 11), and 7 (21%) without PTSD (BASE group). Eight-week outcomes for the MBX group were superior to those for the control group (mean difference for PCL-C scores, -13.6; 95% confidence interval [CI], -25.6, -1.6; P = .01; mean difference for serum cortisol, 5.8; 95% CI, 0.83, 10.8; P = .01). No significant differences were identified between groups in any other items. The changes in the MBX group were maintained at the 16-week follow-up (P = .85 for PCL-C; P = .21 for cortisol). Our data show that improved PTSD scores were associated with normalization of cortisol levels (P < .05). CONCLUSIONS The results suggest that MBX appears to reduce the prevalence of PTSD-like symptoms in individuals exhibiting subclinical features of PTSD.


Medicine and Science in Sports and Exercise | 1997

Exercise mode and gender comparisons of energy expenditure at self-selected intensities

Len Kravitz; Robert A. Robergs; Vivian H. Heyward; Dale R. Wagner; Kevin Powers

The purpose of this study was to compare oxygen consumption (VO2) and energy expenditure after 20 min of self-selected submaximal exercise for four modes of exercise. Eighteen subjects (9 male and 9 female) first completed a test of VO2max during treadmill running. On separate days, subjects then completed 20 min submaximal treadmill running (TR), simulated cross-country skiing (XC), cycle ergometry (CE), and aerobic riding (AR) exercise. Total VO2 and energy expenditure were significantly higher for TR than all other modes for both males and females (43.6 +/- 10.4, 39.1 +/- 9.7, 36.1 +/- 7.6, 28.4 +/- 6.1 LO2, for TR, XC, CE, and AR, respectively, P < 0.0001). For males and females, heart rate was similar during TR and XC and lower during CE and AR (154.8 +/- 14.2, 152 +/- 13.1, 143.4 +/- 14.9, and 126.2 +/- 12.0 beats.min-1 for TR, XC, CE, and AR, respectively, P < 0.0001). Compared with females, males had significantly greater VO2 (P < 0.005) and energy expenditure (P < 0.004), while females had higher heart rates (P < 0.003). Ratings of perceived exertion (RPE) were not different between TR, XC, and CE, but were significantly lower during AR (13.4 +/- 1.3, 13.6 +/- 0.8, 13.2 +/- 0.9, and 12.6 +/- 1.0 for TR, XC, CE, and AR, respectively, P < 0.003). TR elicited the greatest VO2 and energy expenditure during self-selected exercise despite and RPE similar to XC and CE. Therefore, treadmill exercise may be the modality of choice for individuals seeking to improve cardiorespiratory endurance and expend a larger number of kjoules.


Journal of Applied Physiology | 2014

Effects of oral glutamine supplementation on exercise-induced gastrointestinal permeability and tight junction protein expression

Micah Zuhl; Kathryn R. Lanphere; Len Kravitz; Christine M. Mermier; Suzanne M. Schneider; Karol Dokladny; Pope Moseley

The objectives of this study are threefold: 1) to assess whether 7 days of oral glutamine (GLN) supplementation reduces exercise-induced intestinal permeability; 2) whether supplementation prevents the proinflammatory response; and 3) whether these changes are associated with upregulation of the heat shock response. On separate occasions, eight human subjects participated in baseline testing and in GLN and placebo (PLA) supplementation trials, followed by a 60-min treadmill run. Intestinal permeability was higher in the PLA trial compared with baseline and GLN trials (0.0604 ± 0.047 vs. 0.0218 ± 0.008 and 0.0272 ± 0.007, respectively; P < 0.05). IκBα expression in peripheral blood mononuclear cells was higher 240 min after exercise in the GLN trial compared with the PLA trial (1.411 ± 0.523 vs. 0.9839 ± 0.343, respectively; P < 0.05). In vitro using the intestinal epithelial cell line Caco-2, we measured effects of GLN supplementation (0, 4, and 6 mM) on heat-induced (37° or 41.8°C) heat shock protein 70 (HSP70), heat shock factor-1 (HSF-1), and occludin expression. HSF-1 and HSP70 levels increased in 6 mM supplementation at 41°C compared with 0 mM at 41°C (1.785 ± 0.495 vs. 0.6681 ± 0.290, and 1.973 ± 0.325 vs. 1.133 ± 0.129, respectively; P < 0.05). Occludin levels increased after 4 mM supplementation at 41°C and 6 mM at 41°C compared with 0 mM at 41°C (1.236 ± 0.219 and 1.849 ± 0.564 vs. 0.7434 ± 0.027, respectively; P < 0.001). GLN supplementation prevented exercise-induced permeability, possibly through HSF-1 activation.


Journal of Strength and Conditioning Research | 2008

Evaluation of the BOD POD for estimating percent body fat in collegiate track and field female athletes: a comparison of four methods.

Keren M Bentzur; Len Kravitz; Donna W Lockner

Bentzur, KM, Kravitz, L, and Lockner, DW. Evaluation of the BOD POD for estimating percent body fat in collegiate track and field female athletes: a comparison of four methods. J Strength Cond Res 22(6): 1985-1991, 2008-This investigation examined the accuracy of the BOD POD on a group of Division I collegiate track and field female athletes (N = 30). Hydrostatic weighing (HW) was used as the gold standard method. Body density (Db) values obtained from the BOD POD (DbBP) were compared with those determined by HW (DbHW). Both Db values were converted to percent body fat (%BF) using the Siri equation for comparison. Percent body fat values obtained from the BOD POD (BFBP) were also compared with those obtained from dual-energy X-ray absorptiometry (DXA, BFDXA) and skinfold (SF, BFSF). The validity of the BOD POD was assessed using repeated-measures analysis of variance (ANOVA), and the relationship between the methods was examined through Pearson correlation. Average DbBP was 0.00890 g·cm−3 lower (p < 0.05) than DbHW, resulting in a significant overestimation of %BF (p < 0.05) by the BOD POD. Values for BFDXA and BFBP also differed significantly (p < 0.05). On the other hand, BFSF and BFBP were not significantly different. The correlation between percent body fat values obtained from HW (BFHW) and BFBP was good (r = 0.88, SEE = 2.30) as well as between BFSF and BFBP (r = 0.85, SEE = 2.05). Conversely, the correlation between BFDXA and BFBP was poor (r = 0.25, SEE = 5.73). The strong correlation between BFBP and BFHW presented here suggests that the BOD POD has the potential to be used as a body composition analysis tool for female athletes. The advantages of the BOD POD over HW encourage further investigation of this instrument. However, the fact that the BOD POD and SF results did not differ significantly might suggest that the SF could be used in its place until a better rate of accuracy for this instrument is established.


Nutrition | 2014

Potential role of meal frequency as a strategy for weight loss and health in overweight or obese adults.

Michelle G. Kulovitz; Len Kravitz; Christine M. Mermier; Ann L. Gibson; Carole A. Conn; Deborah Kolkmeyer; Chad M. Kerksick

Improved dietary strategies for weight loss are necessary to decrease metabolic disease risk in overweight or obese adults. Varying meal frequency (MF; i.e., increasing or decreasing eating occasions beyond the traditional pattern of three meals daily) has been thought to have an influence on body weight regulation, hunger control, and blood markers of health. It is common practice for weight management clinicians to recommend increasing MF as a strategy for weight management and to improve metabolic parameters. However, limited research exists investigating the effect of MF during controlled hypocaloric dietary interventions. Furthermore, MF literature often speculates with regard to efficacy of MF treatments based on research using normal weight, overweight/obese, or some combination, where much diversity exists within these various populations. In this review, we suggest that normal-weight and overweight/obese populations, as well as free-living versus investigator-controlled research trials, should be studied independently. Therefore, the objective of the present review is to survey the literature to assess whether the alteration of MF influences body weight regulation, hunger control, and/or blood markers of health in overweight/obese participants undergoing a controlled hypocaloric diet to induce weight loss. Findings of this review indicate that there is uncertainty in the literature when interpreting the optimal MF for obesity treatment, where reduced MF may even show more favorable lipid profiles in obese individuals compared with increased MF. Furthermore, the simple relationship of comparing MF with body fatness or body mass index should also consider whether eating frequency is associated with other healthy factors (e.g., increased physical activity).


Clinical Biomechanics | 2016

The effects of gait retraining in runners with patellofemoral pain: A randomized trial

Jenevieve L. Roper; Elizabeth M. Harding; Deborah Doerfler; James G. Dexter; Len Kravitz; Janet S. Dufek; Christine M. Mermier

BACKGROUND Running popularity has increased resulting in a concomitant increase in running-related injuries with patellofemoral pain most commonly reported. The purpose of this study was to determine whether gait retraining by modifying footstrike patterns from rearfoot strike to forefoot strike reduces patellofemoral pain and improves associated biomechanical measures, and whether the modification influences risk of ankle injuries. METHODS Sixteen subjects (n=16) were randomly placed in the control (n=8) or experimental (n=8) group. The experimental group performed eight gait retraining running sessions over two weeks where footstrike pattern was switched from rearfoot strike to forefoot strike, while the control group performed running sessions with no intervention. Variables were recorded pre-, post-, and one-month post-running trials. FINDINGS Knee pain was significantly reduced post-retraining (P<0.05; effect size=0.294) and one-month follow-up (P<0.05; effect size=0.294). Knee abduction was significantly improved post-retraining (P<0.05; effect size=0.291) and one-month follow-up (P<0.05; effect size=0.291). Ankle flexion was significantly different post-retraining (P<0.05; effect size=0.547), as well as ankle range of motion post-retraining (P<0.05; effect size=0.425) and one-month follow-up (P<0.05; effect size=0.425). INTERPRETATION Findings suggest running with a forefoot strike pattern leads to reduced knee pain, and should be considered a possible strategy for management of patellofemoral pain in recreational runners. This trial is registered at the US National Institutes of Health (clinicaltrials.gov) #NCT02567123.


Journal of Strength and Conditioning Research | 2006

Development of a Submaximal Test to Predict Elliptical Cross-Trainer Vo2max

Lance C. Dalleck; Len Kravitz; Robert A. Robergs

The purpose of this study was to develop an equation to predict VO2max from a submaximal elliptical cross-trainer test. Fifty-four apparently healthy subjects (25 men and 29 women, mean +/- SD age: 29.5 +/- 7.1 years, height: 173.3 +/- 12.6 cm, weight: 72.3 +/- 7.9 kg, percent body fat: 17.3 +/- 5.0%, and elliptical cross-trainer VO2max: 43.9 +/- 7.2 ml x kg(-1) x min(-1)) participated in the study and were randomly assigned to an original sample group (n = 40) and a cross-validation group (n = 14). Each subject completed an elliptical cross-trainer submaximal (3 5-minute submaximal stages) and a VO2max test on the same day, with a 15-minute rest period in between. Stepwise multiple regression analyses were used to develop an equation for estimating elliptical cross-trainer VO2max from the data of the original sample group. The accuracy of the equation was tested by using data from the cross-validation group. Because there was no shrinkage in R2 between the original sample group and the cross-validation group, data were combined in the final prediction equation (R2 = 0.732, standard error of the estimate = 3.91 ml x kg(-1) x min(-1), p < 0.05): VO2max = 73.676 + 7.383(gender) - 0.317(weight) + 0.003957(age x cadence) - 0.006452(age x heart rate at stage 2). The correlation coefficient between the predicted and measured VO2max values was r = 0.86. Dependent t-tests resulted in no significant differences (p > 0.05) between predicted (43.8 ml x kg(-1) x min(-1)) and measured (43.9 ml x kg(-1) x min(-1)) VO2max measurements. Results indicate that the protocol and equation developed in the current study can be used by exercise professionals to provide acceptably accurate estimates of VO2max in non-laboratory-based settings.


Medicine and Science in Sports and Exercise | 2010

Palm Cooling Delays Fatigue during High-Intensity Bench Press Exercise

Young Sub Kwon; Robert A. Robergs; Len Kravitz; Burke Gurney; Christine M. Mermier; Suzanne M. Schneider

UNLABELLED Local cooling can induce an ergogenic effect during a short-term intense exercise. One proposed method of personal cooling involves heat extraction from the palm. PURPOSE In this study, we hypothesized that local palm cooling (PC) during rest intervals between progressive weight training sets will increase total repetitions and exercise volume in resistance-trained subjects exercising in a thermoneutral (TN) environment. METHODS Sixteen male subjects (mean +/- SD; age = 26 +/- 6 yr, height = 178 +/- 7 cm, body mass = 81.5 +/- 11.3 kg, one-repetition maximum (1RM) bench press = 123.5 +/- 12.6 kg, weight training experience = 10 +/- 6 yr) performed four sets of 85% 1RM bench press exercise to fatigue, with 3-min rest intervals. Exercise trials were performed in a counterbalanced order for 3 d, separated by at least 3 d: TN, palm heating (PH), and PC. Heating and cooling were applied by placing the hand in a device called the rapid thermal exchanger, set to 45 degrees C for heating or 10 degrees C for cooling. This device heats or cools the palm while negative pressure (-35 to -45 mm Hg) is applied around the hand. RESULTS Total exercise volume during the four PC sets (2480 +/- 636 kg) was significantly higher than that during TN (1972 +/- 632 kg) and PH sets (2156 +/- 668 kg, P < 0.01). The RMS of the surface EMG with PC exercise was higher (P < 0.01), whereas esophageal temperature (P < 0.05) and RPE (P < 0.05) were lower during PC compared with TN and PH. CONCLUSIONS PC from 35 degrees C to 20 degrees C temporarily overrides fatigue mechanism(s) during intense intermittent resistance exercise. The mechanisms for this ergogenic function remain unknown.


Open access journal of sports medicine | 2016

Graded Exercise Testing Protocols for the Determination of VO2max: Historical Perspectives, Progress, and Future Considerations

Nicholas M. Beltz; Ann L. Gibson; Jeffrey M. Janot; Len Kravitz; Christine M. Mermier; Lance C. Dalleck

Graded exercise testing (GXT) is the most widely used assessment to examine the dynamic relationship between exercise and integrated physiological systems. The information from GXT can be applied across the spectrum of sport performance, occupational safety screening, research, and clinical diagnostics. The suitability of GXT to determine a valid maximal oxygen consumption (VO2max) has been under investigation for decades. Although a set of recommended criteria exists to verify attainment of VO2max, the methods that originally established these criteria have been scrutinized. Many studies do not apply identical criteria or fail to consider individual variability in physiological responses. As an alternative to using traditional criteria, recent research efforts have been directed toward using a supramaximal verification protocol performed after a GXT to confirm attainment of VO2max. Furthermore, the emergence of self-paced protocols has provided a simple, yet reliable approach to designing and administering GXT. In order to develop a standardized GXT protocol, additional research should further examine the utility of self-paced protocols used in conjunction with verification protocols to elicit and confirm attainment of VO2max.

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Todd Astorino

California State University San Marcos

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Robert Robergs

University of South Wales

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Derek Marks

California State University

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Frank Wyatt

Midwestern State University

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