Sharon R. Rana

Mets and Accelerometry of Walking in Older Adults: Standard versus Measured Energy Cost

PURPOSE This study aimed to measure the metabolic cost (METs) of walking activities in older adults, to examine the relationship between accelerometer output and METs across walking activities, and to compare measured MET values in older adults with the MET values in the compendium. METHODS Twenty older adults (mean age = 75, range = 60-90 yr) completed eight walking activities (five treadmill based, three free living) for 6 min each. Oxygen consumption (V˙O2) and resting metabolic rate (RMR) were measured using a portable metabolic system, and motion was recorded using a waist-mounted ActiGraph accelerometer (GT3X; ActiGraph, Pensicola, FL). Energy expenditure across activities was defined as kilocalories per minute and measured as METs (V˙O2 / RMR) and standard METs (V˙O2 / 3.5 mL·kg-1·min-1). Mixed modeling was used to assess differences in counts per minute and kilocalories per minute by weight status, sex, comorbidity status, and functional status. Linear regression analysis was applied to develop a prediction equation for kilocalories per minute. Energy costs of walking were subsequently compared with METs in the compendium of physical activities. RESULTS Average measured RMR was 2.6 mL·kg-1·min-1, 31.6% less than the standard RMR of 3.5 mL·kg-1·min-1. On average, standard METs were 71% lower than the measured METs across all walking activities. Measured MET levels differed from previously reported values in the literature and values listed in the compendium, resulting in misclassification of activity intensities for 60% of the walking conditions. Average counts for the walking activities ranged from 809 (treadmill = 1.5 mph) to 4593 counts per minute (treadmill = 3.5 mph). Previous regression equations consistently overestimate all activities compared with the measured energy cost in this sample of older adults. CONCLUSION This study identifies the need for equations and cut points specific to older adults.

Comparison of early phase adaptations for traditional strength and endurance, and low velocity resistance training programs in college-aged women

The purpose of this study was to investigate the effects of a six-week (16-17 training sessions) low velocity resistance training program (LV) on various performance measures as compared to a traditional strength (TS) and a traditional muscular endurance (TE) resistance training program. Thirty-four healthy adult females (21.1 ± 2.7 y) were randomly divided into 4 groups: control (C), TS, TE, and LV. Workouts consisted of 3 exercises: leg press (LP), back squat (SQ), and knee extension (KE). Each subject was pre- and posttested for 1 repetition maximum (1RM), muscular endurance, maximal oxygen consumption (VO2max), muscular power, and body composition. After the pretesting, TS, TE, and LV groups attended a minimum of 16 out of 17 training sessions in which the LP, SQ, and KE were performed to fatigue for each of 3 sets. For each training session, TS trained at 6-10 RM and TE trained at 20-30 RM both with 1-2 second concentric/1-2 second eccentric; and LV trained at 6-10 RM, with 10 second concentric/4 s eccentric. Statistical significance was determined at an alpha level of 0.05. LV increased relative LP and KE 1 RM, but the percent increase was smaller than TS, and not different from C in the SQ. For muscular endurance, LV improved similarly to TE for LP and less than TS and TE for KE. Body composition improved for all groups including C (significant main effect). In conclusion, muscular strength improved with LV training however, TS showed a larger improvement. Muscular endurance improved with LV training, but not above what TE or TS demonstrated. For all other variables, there were no significant improvements for LV beyond what C demonstrated.

Effect of the Wingate Test on Mechanomyography and Electromyography

The purpose of this investigation was to examine mechanomyographic (MMG) and electromyographic (EMG) amplitude responses of the superficial quadriceps femoris muscles during the Wingate Anaerobic Test (WAnT). Ten healthy adults (age 21 6 1.2 years) volunteered to perform the WAnT on a calibrated Monark 894E cycle ergometer while the EMG and MMG signals were recorded. The EMG and MMG amplitude and power output (W) values per 5-second segments of the test were averaged and normalized to the highest value found during the test, respectively. The statistical analysis indicated that EMG amplitude did not change significantly over the 30-second test, but W and MMG amplitude decreased significantly. There is dissociation between EMG and MMG amplitude over the 30-second anaerobic test, providing evidence that MMG amplitude could be used as a monitor of W during such a task. MMG amplitude could potentially be used as a direct monitor of mechanical activity, which could be of benefit to those who train athletes when a direct assessment of mechanical contribution from a given muscle to a fatiguing activity is desired (such as when monitoring an injury), but it must be studied under various conditions, such as the current study, before such applications are made.

Physiological profile of women's Lacrosse players.

Enemark-Miller, EA, Seegmiller, JG, and Rana, SR. Physiological profile of womens lacrosse players. J Strength Cond Res 23(1): 39-43, 2009-Increasing participation rates for womens lacrosse necessitate a clear understanding of fitness parameters for this athlete group. However, limited sport-specific information is available. We described the physiological profile of an NCAA Division I womens lacrosse team to provide current data for this specific athlete group. A descriptive analysis was used to assess physiologic variables. Twenty-four members (age 20.0 ± 1.4 years, mass 64.7 ± 9.6 kg, height 163.2 ± 25.6 cm) of an NCAA Division I womens lacrosse team volunteered and provided consent. Fitness tests were conducted by the same researcher and were selected from standard physical fitness assessments. Tests included cardiovascular endurance (Bruce Protocol &OV0312;o2max test and 1-mile run), flexibility (sit-and-reach test), muscular endurance (push-ups, sit-ups, and 60% of 1RM back squat), muscular strength (one-repetition maximum [1RM] back squat and 1RM bench press), body composition (BOD POD), muscle torque (quadriceps maximal voluntary isometric contraction), grip strength (hand dynamometer), vertical jump (Vertec vertical column), endurance strength (100- and 200-yard sprints), and Q-angle. Our results indicate that our sample of lacrosse players exhibited similar fitness characteristics to basketball, soccer, and track athletes. However, we found only average flexibility and a higher percentage of body fat, indicating possible areas for improvement in lacrosse training programs.

Using a practical approach for determining the most effective stretching strategy in female college division I volleyball players.

Abstract Kruse, NT, Barr, MW, Gilders, RM, Kushnick, MR, and Rana SR. Using a practical approach for determining the most effective stretching strategy in female college division I volleyball players. J Strength Cond Res 27(11): 3060–3067, 2013—The purpose of this investigation was to quantify the effects that a practical bout of static stretching (SS) and dynamic stretching (DS) has on maximal countermovement jump (CMJ) height across a time spectrum of 25 minutes in National Collegiate Athletic Association Division I varsity volleyball players. Eleven female varsity volleyball players (mean ± SD; age 20.00 ± 1.55 years; height 1.78 ± 0.08 m; mass 74.55 ± 12.18 kg) volunteered for this investigation. Three days of randomized experimental testing (SS, DS, control) were completed. The SS protocol consisted of stretching 7 muscle groups. The DS protocol consisted of the volleyball teams actual DS routine of equal duration (30 seconds) to SS. Poststretch performance measures of CMJ were determined at 1, 5, 15, and 25 minutes poststretch. Countermovement jump had an acute significant trial-by-time interaction, indicating that DS was found to produce significantly higher scores than the SS and control session at 1 and 5 minutes poststretch, but not at 15 and 25 minutes poststretch. Additionally, there was a timing interaction within trials where SS scores were significantly lower at 1minute poststretch compared with 5 and 25 minutes poststretch, and DS scores were significantly higher at 1 and 5 minutes poststretch compared with 15 and 25 minutes poststretch. Athletes engaging in competitive power sports should continue to utilize their DS routine but may need to do so within 5 minutes before activity.

Comparison of mechanomyographic sensors during incremental cycle ergometry for the quadriceps femoris

The purpose of this study was to examine the mechanomyographic (MMG) amplitude and mean power frequency (MPF) versus power output relationships for the vastus lateralis and rectus femoris muscles during incremental cycle ergometry between the piezoelectric contact sensor (HP) and the accelerometer (ACC) sensor. Nine men performed an incremental cycle ergometry test to voluntary exhaustion. Polynomial regression analyses on a subject‐by‐subject basis indicated that the relationship between the normalized MMG amplitude versus normalized power output was best fit with either a linear, quadratic, or cubic model. These patterns were consistent between sensors for each muscle for each subject. No consistent relationship was found for MMG MPF within subjects and between muscle groups. In addition, there were no significant sensor × power output interactions for normalized MMG amplitude or MPF. These results suggest that, for cycle ergometry, the HP and ACC sensors provide similar information for the interpretation of motor control strategies during continuous exercise. Muscle Nerve, 2010

Accuracy of near-infrared interactance instruments and population-specific equations for estimating body composition in young wrestlers.

&NA; Housh, T.J., G.O. Johnson, D.J. Housh, J.T. Cramer, J.M. Eckerson, J.R. Stout, A.J. Bull, and S.R. Rana. Accuracy of near‐infrared interactance instruments and population‐specific equations for estimating body composition in young wrestlers. J. Strength Cond. Res. 18(3):556–560.—The purpose of this investigation was to determine the accuracy of near‐infrared interactance (NIR) instruments and population‐specific NIR equations for estimating percent body fat (% fat) in young wrestlers. Forty‐four white male youth wrestlers (mean age ± SD = 11.0 ± 2.1 years) volunteered for this study. Thirteen NIR % fat estimates were cross‐validated against the criterion % fat from underwater weighing. The results of this study indicated that the total error (TE) values associated with the NIR instrument generated % fat estimates as well as % fat estimates from population‐specific NIR equations developed for high school wrestlers or adult men were too large (TE = 5.7–27.3% fat) to be used with young wrestlers. Based on the present findings, it is recommended that new NIR equations be developed and validated specifically for use in young male athletes.

Excess post‐exercise oxygen consumption is not associated with mechanomyographic amplitude after incremental cycle ergometry in the quadriceps femoris muscles

Introduction: The purpose of this study was to understand the relationship between the mechanical activities of the three superficial quadriceps muscles and excess post‐exercise oxygen consumption (EPOC) after incremental cycle ergometer exercise. Methods: Twelve healthy male volunteers had mechanomyographic (MMG) and electromyographic (EMG) activity of the superficial quadriceps muscles recorded 30 minutes before incremental cycle ergometry and 60 minutes after the exercise work bout. Results: The results indicate significant time‐constant values for EPOC and MMG amplitude for the three superficial quadriceps muscles during the 60‐minute post‐exercise recovery period. For EMG amplitude no decay patterns were found for the three muscles. In addition, there were no mean differences between the MMG values for the three muscles that were significantly different from EPOC. Conclusions: These results suggest that EPOC after exercise could not be exclusively attributed to elevated activity of the working muscles. Muscle Nerve 44: 432–438, 2011

Comparison of Physiological Variables Between the Elliptical Bicycle and Run Training in Experienced Runners

Abstract Klein, IE, White, JB, and Rana, SR. Comparison of physiological variables between the elliptical bicycle and run training in experienced runners. J Strength Cond Res 30(11): 2998–3006, 2016—A novel outdoor elliptical bicycle (EBIKE) has been designed to elicit running-similar physiological adaptations while reducing the impact forces that commonly lead to injury. Various cross-training methods have been used to reduce injury risk, restore or maintain fitness, and prevent detraining. The purpose of this study was to compare 4 weeks of EBIKE-only training to run-only training on maximal oxygen consumption, ventilatory threshold, respiratory compensation point, running economy, and 5,000 m time trial times. Twelve experienced runners (age, 22.33 ± 3.33 years; running experience, 9.25 ± 4.53 years) completed 4 weeks of randomly assigned EBIKE or run training. Physiological and performance testing procedures were repeated, and subjects then performed a second matched 4-week training period in a crossover design. Ventilatory threshold was significantly greater after EBIKE (p ⩽ 0.05; 41.60 ± 6.15 ml·kg−1·min−1) and run training (p ⩽ 0.05; 42.33 ± 6.96 ml·kg−1·min−1) compared with the initial time point (40.17 ± 6.47 ml·kg−1·min−1). There were no significant group differences (p > 0.05) for these variables at any time point. In conclusion, EBIKE-only training yielded similar physiological and performance maintenance or improvements compared with run-only training. These results suggest that EBIKE training can be an effective cross-training method to maintain and improve certain physiological and performance variables in experienced runners over a 4-week period.

A Purposeful Dynamic Stretching Routine.

May/June 2012 Dynamic stretching, which involves moving parts of the body and gradually increases range of motion, speed of movement, or both through controlled, sport-specific movements, has become the popular choice of pre-exercise warm-up (Woods, Bishop, & Jones, 2007). This type of warm-up has evolved to encompass several variations, but at its core is the principle theme that preparing the body for exercise can be achieved best through continuous, coordinated movement. Dynamic stretching improves flexibility, while simultaneously increasing body heat and blood flow, all of which are important to warming up for a race (McMillian, Moore, Hatler, & Taylor, 2006). By increasing range of motion, dynamic stretching serves as a possible preventative measure against injuries. Furthermore, dynamic stretching is a more functional way to prepare the body for exercise, because it also increases the core temperature of the body (Mann & Whedon, 2001). For the majority of sports, everything that is needed in a proper warm-up can be found through dynamic stretching. Dynamic stretching has been defined as large body movements often combined with typical running drills in multiple directions (i.e., lunging and squatting, change-indirection) (McMillian et al. 2006). For distance running and other sports with a running component, an increased range of motion can potentially increase stride length, which will allow runners to be able to cover more ground over a shorter period of time. For distance running in particular, the debate exists as to what stretching method (static or dynamic) should be used as a pre-run warm up. Static stretching is the stretching of a muscle or muscle group to its furthest point and holding that position for 10-30 seconds (Mann & Whedon, 2001). Static stretching has long been a staple in many runners’ prerun routine and is viewed as the easiest and safest way to stretch (Mann & Whedon, 2001). However, recent developments in scientific research have indicated that static stretching might not be the most efficient or effective way to prepare distance runners for their upcoming event (McMillian et al. 2006). A recent publication in Strategies (Vardiman, Carrand, & Gallagher, 2010) addressed dynamic stretching but not specific to distance runners. Therefore, the purpose of this article are twofold: 1) to review the benefits of dynamic stretching for distance runners, and 2) to provide distance runners and coaches with a detailed dynamic stretching routine that can be adopted. All suggestions made within this article can easily be transferred to other sports, especially those that contain a running component.