Amy L. Morgan

Effects of Resistance Training on Functional Ability in Elderly Individuals

Purpose. Determine the effects of 16 weeks of strength training on measures of functional ability in elderly who are functionally limited. Design. Quasi-experimental trial in which elderly volunteers were assigned to either an exercise group or a control group. Participants. Eighty-seven participants (65–93 years) living independently but with some functional limitations. Intervention. Thirteen different strength training exercises using Thera-Band resistive bands (Hygenic Corporation, Akron, Ohio). The program was 16 weeks in duration, and the frequency was three times per week. Participants exercised in a group setting one time per week and were given a home exercise book to follow for two additional sessions per week. Measures. Functional ability was operationalized to include a variety of measures related to functional ability that impact activities of daily living, morbidity, and mortality in the elderly, including upper- and lower-body strength and gait. Analysis. Intervention effects were analyzed using a 2 (groups: exercise group vs. control group) X 3 (time: baseline vs. mid vs. post) analysis of variance. Results. The exercise group demonstrated significant improvements in upper-body strength as measured by biceps curl (F[2,140] = 39.870; p < .05) and lower-body strength as measured by chair sit-to-stand (F[2,124] = 25.887; p < .05). Gait velocity (F[2,140] = 37.317; p < .05) and step length (F[2,140] = 4.182; p < .05) both increased for the exercise group at week 9, but this increase disappeared by week 17. Compared with minimal changes in the control group, the exercise group demonstrated significant improvements in upper-body strength as measured by biceps curl and lower-body strength as measured by chair sit-to-stand. Conclusion. Some measures of function ability were improved after a 16-week structured exercise program for functionally limited elderly. Because functional ability has been inversely correlated with short-term morbidity and the need for assisted living among older adults, providing opportunities to exercise is crucial to future functioning and independence of the elderly population. (Am J Health Promot 2011;25[4]:237–243.)

Exercise and Functional Tasks Among Adults Who Are Functionally Limited

This study compared the efficacy of 16 weeks of either resistance training, aerobic walking, or combined resistance training and aerobic walking on the performance of functional tasks among adults age 65 years and older with limited functional ability. One hundred thirty-one older adult individuals were randomized into four groups: resistance training, aerobic walking, combined resistance and aerobic walking groups, or a nonexercise control group. Each of the exercise groups documented 70% compliance with their respective exercise intervention, which included three weekly exercise sessions. At baseline, and 8 and 16 weeks following baseline, all participants completed six assessments of their functional ability. Analysis of covariance indicated that all three exercise intervention groups significantly improved measures of functional ability, with the resistance group demonstrating the most consistent gains over the six measures. These findings indicate that older adults who are functionally limited can improve their functional ability through a variety of types of exercise.

Monitoring hemodialysis changes with bioimpedance : what do we really measure ?

Changes in electrical resistance (delta R), water (delta H2O), and blood variables (Na+, K+, Cl-, protein [Pr], osmolality [Osmo], hemoglobin [Hb], and hematocrit [Hct]) were monitored during hemodialysis in 20 subjects. Average delta H2O was 1.69 +/- 0.91 liters. Blood, R, and circumferences (C) were measured for the upper limb (UL), lower limb (LL), and total body (TB) before, midway, and at the end of dialysis. Segmental volumes (V) and specific resistivity (rho) were computed. delta Hct and delta Pr were stronger predictors of delta H2O than delta R. Forward stepwise regression analysis using delta R at 5, 50, and 548 kHz, delta Pr, and delta Hct showed that delta Hct and delta Pr alone accounted for 77% of the variance in delta TBW. Adding delta R increased this at most to 81%. Both the UL and LL had significant increases in rho. The volumetric change of the UL was nonsignificant, whereas that of the LL accounted for over one half of the delta H2O. Single frequency bioimpedance cannot be used to monitor dialytic delta H2O unless one accounts for fluid composition changes. Monitoring bioimpedance changes over only a single body segment is also questioned.

Activity-Related Energy Expenditure in Older Adults: A Call for More Research.

The purposes of this article were to 1) provide an overview of the science of physical activity-related energy expenditure in older adults (≥65 yr), 2) offer suggestions for future research and guidelines for how scientists should be reporting their results in this area, and 3) present strategies for making these data more accessible to the layperson. This article was meant to serve as a preliminary blueprint for future empirical work in the area of energy expenditure in older adults and translational efforts to make these data useful and accurate for older adults. This document was based upon deliberations of experts involved in the Strategic Health Initiative on Aging Committee of the American College of Sports Medicine. The article was designed to reach a broad audience who might not be familiar with the complexities of assessing energy expenditure, especially in older adults.

Hydration status of community-dwelling seniors.

Background and aims: Dehydration is the most common fluid or electrolyte disorder among older persons. This study was designed to examine the hydration status of community-dwelling seniors. Methods: Blood and urine samples were collected from 67 independently living volunteers (65–93 yrs) who had functional limitations but no condition that contraindicated 10 min of moderate exercise. Forty-six subjects who were not diabetic, had fasted for 12 hours, and had blood glucose levels ≤115 mg/dL were thus included. Urine and serum samples were analyzed for osmolality (mosm/kg), Na+ (mmol/L) and K+ (mmol/L). Whole blood was analyzed for hemoglobin (Hb, g/dL) and hematocrit (Hct, %) and urine for specific gravity (USG). Means and standard deviations for the current data were compared with normal values. Results: All values were within normal ranges except urine osmolality. Conclusions: While changes associated with aging may predispose an individual to dehydration, functionally limited, independently living older individuals demonstrate normal hydration status following a 12-hr fast. This suggests that dehydration is not solely a function of the aging process, but may be more related to concomitant medical conditions or dependent living.

Comparison of V[combining Dot Above]o2peak Performance on a Motorized vs. a Nonmotorized Treadmill

Abstract Morgan, AL, Laurent, CM, and Fullenkamp, AM. Comparison of V[Combining Dot Above]O2peak performance on a motorized vs. a nonmotorized treadmill. J Strength Cond Res 30(7): 1898–1905, 2016—Despite growing popularity of nonmotorized treadmills (NMTs), little data exist regarding responses during exercise testing using this equipment, which is important when providing an appropriate exercise prescription. The purpose of this study was to evaluate physiological and perceptual responses during peak graded exercise tests (GXTs) on a motorized treadmill (MT) vs. NMT. Volunteers (12 men and 12 women aged 18–35 years) performed 2 peak GXT sessions (1 MT and 1 NMT). Respiratory gases and heart rate (HR) were collected each minute; perceptual response was estimated (Borgs 6–20 rating of perceived exertion [RPE] scale) during the final 10 seconds of each stage. Peak values (i.e., V[Combining Dot Above]O2, HR, speed) were determined during the final 10 seconds of each test; ventilatory threshold (VT) was assessed using the V-slope method. Paired t-tests matching variables measured at each stage of the GXT identified significantly higher values on the NMT for V[Combining Dot Above]O2 83% of the time, HR 67% of the time, and RPE 25% of the time. Interestingly though, neither peak V[Combining Dot Above]O2 (48.6 ± 9.2 ml·kg·min−1 vs. 47.8 ± 8.9 ml·kg·min−1), peak HR (185 ± 9 b·min−1 vs. 188 ± 10 b·min−1; p = 0.90), nor VT (72.7 ± 5.7% vs. 73.8 ± 5.4%) were significantly different on the NMT vs. the MT. However, significant differences were identified between NMT and MT tests for time to exhaustion (9:55 ± 1:49 vs. 12:05 ± 2:48; p < 0.01) and peak speed (8.0 ± 0.9 mph vs. 9.2 ± 1.4 mph; p < 0.01). Thus, although peak values obtained were similar between testing sessions on the NMT and MT, the majority of submaximal data were significantly different between trials. These differences are important when designing exercise prescriptions using submaximal values from NMT testing that may be inappropriately high or low at corresponding intensities during training.

Relationship Between Body Fat and Physical Fitness in Army ROTC Cadets

The Army Physical Fitness Test (APFT), including timed push-ups, sit-ups, and run, assesses physical performance for the Army. Percent body fat is estimated using height and circumference measurements. The objectives of the study were to (a) compare the accuracy of height and circumference measurements to other, more accepted, body fat assessment methods and (b) determine the relationships between body composition and APFT results. Participants included Reserve Officer Training Corps (ROTC) cadets (n = 11 males, 2 females, 21.6 ± 3.5 years) from a midwestern university). At one visit, percent body fat was assessed using height and circumference measurements, air-displacement plethysmography, and bioelectrical impedance analysis. APFT results were provided by the ROTC director. All assessment methods for percent body fat were strongly associated (r ≥ 0.7, p < 0.01), implying that height and circumference measurement is a practical tool to estimate percent body fat of ROTC cadets. Total APFT score was not associated with any body fat assessment method. Push-up number was negatively associated with percent body fat by all assessment methods (r ≥ -0.8, p = 0.001), although run time was positively associated (r ≥ 0.6, p < 0.05). This suggests that percent body fat may be an important variable in determining or improving cardiovascular and muscular endurance, but not APFT performance.

Power, fatigue, and recovery changes in national collegiate athletic association division I hockey players across a competitive season.

Abstract Laurent, CM, Fullenkamp, AM, Morgan, AL, and Fischer, DA. Power, fatigue, and recovery changes in National Collegiate Athletic Association Division I hockey players across a competitive season. J Strength Cond Res 28(12): 3338–3345, 2014—This study aimed to evaluate changes in pre- to postseason power output, fatigue, and recovery during a repeated sprint test. Twenty National Collegiate Athletic Association Division I mens hockey athletes performed identical sessions of repeated sprint work pre- and postseason. The repeated sprint test consisted of 5 sets of 45 seconds of repeated sprint work with 90 seconds of rest in between each series of sprints. Power output (W), decrement, and recovery scores (RECs) were determined using raw data from a nonmotorized treadmill. Ratings of perceived exertion were recorded after, and perceived readiness (PR) recorded before, each series of sprints. Mean power was significantly higher in preseason vs. postseason performance during sprint 1 (760.6 vs. 691.3 W; p = 0.03), sprint 2 (719.9 vs 657.0 W; p = 0.05), sprint 4 (648.4 vs 588.9 W; p = 0.04), and sprint 5 (656.6 vs. 586.8 W, p = 0.04). Ratings of perceived exertion were significantly higher during sprints 3, 4, and 5 postseason with PR significantly higher (indicating less readiness) before sprints 3 and 4. There were no significant differences in REC or decrement score. Overall, athletes were unable to maintain power during subsequent repeated sprint work during postseason. The degree to which the athletes fatigued and recovered between sprints did not change between pre- and postseason testing, however, athletes exhibit increased perceptual strain during the repeated sprint work. These data indicate meaningful performance and perceptual differences throughout the competitive season in collegiate-level hockey players.

An Evaluation of Upper-Body Muscle Activation during Coupled and Uncoupled Instability Resistance Training.

Abstract Campbell, BM, Kutz, MR, Morgan, AL, Fullenkamp, AM, and Ballenger, R. An evaluation of upper-body muscle activation during coupled and uncoupled instability resistance training. J Strength Cond Res 28(7): 1833–1838, 2014—Recently, there has been a growth in the popularity of resistance exercises performed on unstable surfaces. However, the relationship between unstable surface training and load coupling on muscle activation is unclear. The purpose of this study was to evaluate changes in muscle activation during a barbell (BB) (coupled) and dumbbell (DB) (uncoupled) chest press exercise performed on an unstable surface. The 3 specific chest press conditions included 50% 1 repetition maximum (RM) with BB (50% BB), 50% 1RM with DBs (50% DB), and 25% 1RM with DBs (25% DB). Ten male subjects participated in the study (age, 23.9 ± 2.6 years; body weight, 82.8 ± 10.2 kg). During testing, mean electromyographic activity was assessed for pectoralis major (PM), triceps brachii, anterior deltoid (AD), and rectus abdominis (RA) and was presented as a percent change across the lifting conditions. It was observed that muscle activation increased by 15% in both the PM and RA from the 50% BB condition to the 50% DB condition. Also, the greatest percent difference in muscle activation between the 50 and 25% DB conditions occurred for PM and AD (+54% during 50% DB). These results suggest that demands on the core musculature to provide stability are increased with the use of DBs (uncoupled) as opposed to a BB (coupled). Where instability training provides a sufficient hypertrophy stimulus in prime mover muscle groups, there may be the added benefit of core stability training. Specifically, this type of training may benefit both untrained persons and those engaged in active rehabilitation.

First-Year University Students Who Self-Select into Health Studies Have More Desirable Health Measures and Behaviors at Baseline but Experience Similar Changes Compared to Non-Self-Selected Students

Studies demonstrate that first-year university students are at high risk for weight gain. These reports typically rely on self-selected participants. The purpose of this study was to explore if students who chose to participate in a health-based research study had more desirable health measures and behaviors than students who completed health assessments as part of a first-year seminar course. Health measures included blood pressure (BP), body mass index (BMI), and percent body fat. Health behaviors included dietary patterns (Starting the Conversation questionnaire) and alcohol use (Alcohol Use Disorders Identification Test-Consumption). A total of 191 (77% female) participants completed testing in the self-selected “Health Study” group, whereas 73 of the 91 students (80%, 55% female) enrolled in the “Seminar” allowed their data to be used for research purposes. Baseline measures favored Health Study participants, including but not limited to fewer participants with undesirable BMI (≥25.0 kg/m2; males and females) and a smaller percentage of participants with undesirable BP (systolic ≥120 mmHg and/or diastolic ≥80 mmHg; females only). Differences in dietary behaviors at baseline were inconsistent, but Seminar students engaged in more problematic alcohol-use behaviors. While both groups experienced undesirable changes in health measures over time, the degree of change did not differ between groups. Changes in health behaviors over time typically resulted in undesirable changes in the Seminar group, but the magnitude of change over time did not differ between groups. Thus, results from first-year university students who self-select into health studies likely underestimate the seriousness of undesirable health measures and behaviors but may accurately reflect the degree of change over time.