Electrical stimulation-induced leg cycle ergometry (ES-LCE) can have health and fitness benefits for those with spinal cord injuries. ES-LCE elicits relatively high metabolic rates, but gross efficiency (GE) is very low. To evaluate the effect of cadence on GE of ES-LCE, 6 ES-LCE-trained men with paraplegia performed 15-min periods of ES-LCE at cadences of 32, 39, 49 (=standard cadence), 60 and 70 rpm in a counterbalanced order. ES-LCE at a constant power output (PO) of 3W was performed on an Ergys 2 ergometer, modified to enable setting of various target cadences. Computer-controlled stimulation (rectangular biphasic, 30 Hz, 140 mA max) was applied to the upper-leg and gluteal muscles. To calculate GE during the last 2 min of each period, VO2 and VCO2 were measured by open-circuit spirometry. GE values were very low and decreased (p < 0.05) linearly with increasing cadence: 1.97 ± 0.4% (at 32 rpm), 1.85 ± 0.4% (39), 1.76 ± 0.3% (49), 1.69 ± 0.3% (60), 1.50 ± 0.3% (70 rpm). Stimulation amplitudes increased accordingly from 78 ± 18 at 32 rpm to 112 ± 22 mA at 70 rpm, indicating greater muscle activity needed at higher cadences. As a result, 2 subjects could not maintain 70 rpm for 15 min. The subjects indicated a preference for the higher (≥ 49 rpm) cadences. It was concluded that no optimal cadence was found but that GE of ES-LCE exercise decreases with increasing cadence, which is probably related to the increase in internal work. These results suggest that cadence setting might be used to influence cycling endurance and PO and metabolic rate levels achieved. However, more research is needed to address this effect at different PO levels as well as at maximal exercise.

129 The purpose of this study was to determine relations among subjective clinical ratings, lower-body muscle strength, and functional performance in Parkinson's disease (PD). Eight men (66±14 yr.) and 4 women(66±7 yr.) with PD were clinically rated using the Hoehn and Yahr scale(H&Y) and the Unified Parkinson's Disease Rating Scale (UPDRS) while being off medication. Maximal isometric and isokinetic (60 °/s) concentric/eccentric knee extension torque (Tiso, Tcon, Tecc) of the affected limbs were determined using a Kin-Com II. Functional performance was assessed by a 10-m sit-stand-walk (SSW) test and a gait analysis (Peak Performance). In addition, activity level (total body movement) was recorded during one day using a dual axis mercury motion detector (Mini-Mitter). H&Y and UPDRS were strongly related (r=0.86, p<0.05), but was not significantly related to strength variables, SSW, or activity level, and only moderately (p<0.05) related to self-selected walking velocity (r=0.64, r=0.56) and stride length(r=0.65, r=0.57). More strongly related to walking velocity and SSW performance was Tcon (r=0.72, r=0.60, respectively). Activity level was not significantly related to any variable. These data indicate that subjective clinical ratings are only moderately related to functional performance in PD, suggesting a need for additional objective muscle strength and functional performance tests. TableTable

406 The purpose of this study was to compare the relationships among lower-body muscular strength, rate of force production, and stability in older females with a history of falls (F) to those with no history of falls (NF). Eleven females (6 F, 78.4 and 5 NF 77.9 yrs) were recruited for this study from a geriatric retirement community. Subjects reported to the testing laboratory in the morning and performed all testing procedures during a single session. Skinfold measurements were taken from the triceps and suprailliac to estimate body composition. No significant differences were found between F and NF for age, height, weight, fat-free mass or percent fat. Bi-lateral isokinetic quadriceps muscle performance was measured at 30 and 60 deg/s using a Kin-Com II. Stability and 3-D functional muscle force production were measured using a sit-to-stand test on a Kistler forceplate. Subjects performed 3 maximal efforts on the Kin-Com II with the average being reported. Results indicated that concentric peak torque for both 30 and 60 deg/s was lower for F compared to NF (69.3±18 vs. 80.1±34 Nm, and 83.3±22 vs. 92.2±20 Nm, respectively, p<0.05). Eccentric peak torque was also lower for F compared to NF for both velocities (25.6±19 vs 30.3±15 Nm, and 38.7±9 vs 41.2±28 Nm, respectively, p<0.05). No significant differences were found between R and L for either group. Results of the sit-to-stand test indicated that reaction time was slower for F, 1000 vs. 600 ms (p<0.05). Peak force developed during the sit-to-stand test was also lower for F (210 vs 405 N p<0.05). Time to peak force was longer for F, 2200 vs. 1200 ms (p<0.05). The slopes of the force production curves were also significantly different between F and NF, 0.079 vs. 0.068. These results suggest that F have reduced lower-body muscle performance capabilities and that the sit-to-stand test may be a valid method for evaluating elderly females for potential risk of falls.

153 The purpose of this study was to determine differences in 3D pedal forces and torques, ankle and knee joint forces, and medio-lateral leg restraint forces between electrical stimulation-induced (ES) leg cycle ergometry (LCE) and voluntary (VOL) LCE. Six men with spinal cord injuries (SCI; C5-T7) and 6 weight-matched able-bodied (AB) men performed LCE exercise at 6.3 W on a recumbent LCE device (Ergys-1, Therapeutic Alliances, Inc.) equipped with 3D force pedals and force transducers in both leg restraints. ES-LCE was induced by percutaneous stimulation of the mm. quadriceps, hamstrings, and gluteals. Motion analysis of pedal and limb segments (right leg) and inverse dynamics were used to calculate 3D ankle and knee joint forces. Cycling patterns were similar for both groups, but the ES-LCE pattern seemed less smooth and more erratic. Paired t-tests showed that peak shear (forward) pedal forces and ranges were higher (p<0.05) for ES-LCE (71±11 vs 27±25 N; 54±5 vs 26±8 N, respectively). Peak medio-lateral and downward pedal forces did not significantly differ between groups. Peak ankle joint compression and shear forces were higher (p<0.05) for ES-LCE (98±10 vs 52±9 N; 71±10 vs 23±21 N). Peak knee joint compression forces were higher (p<0.05) for VOL-LCE (111±4 vs 94±13 N), while peak shear forces were higher (p<0.05) for ES-LCE (69±12 vs 23±21 N). Peak medio-lateral forces in both joints were not different between groups. Peak lateral leg restraint forces were higher in ES-LCE(28±6 vs 11±7 N). Peak torques around the x-axis (plantar flexion) and the y-axis (eversion) were higher in ES-LCE (4±1 vs 2±1 Nm; 2±1 vs 0±1 Nm). These data indicate that 3D biomechanics of ES-LCE differ from VOL-LCE which may contribute to the inefficiency of this induced exercise mode.

The net efficiency of electrical stimulation (ES)-induced leg cycling (LC) at 6-30 W in individuals with spinal cord injuries (SCI) was reported to be only 4-5% compared to 8-17% for voluntary (VOL) LC in able-bodied (AB) persons. This inefficiency is apparently related to muscle fiber changes with paralysis, nonphysiologic activation and inappropriate fiber recruitment. But, unfavorable biomechanics may also play a role. The purpose of this pilot study was to determine differences in 3D pedal forces, as well as in medio-lateral leg restraint forces during ES-LC performed by 2 men with SCI compared to those forces during VOL-LC by 2 AB men. LC was performed on a Therapeutic Alliances, Inc. Ergys-1 equipped with 3D force pedals and force transducers in both medio-lateral leg restraints. ES-LC was induced by computer-controlled surface stimulation of the paralyzed quadriceps, hamstrings, and gluteals. All subjects performed 3-min bouts of LC at 0, 3.1, and 6.3 W, each preceded by a 5-min rest and 1 min of passive pedaling. Although the force application pattern for ES-LC was more consistent over consecutive cycles than for VOL-LC, force patterns in all 3 directions were generally less smooth and more erratic. Mean (±SD) ranges in shear and normal pedal forces were larger for ES-LC (62.5±19.7 N and 55.0±16.4 N, respectively) than for VOL-LC (20.0±11.4 N and 43.2±9.8 N). Mean ranges in medio-lateral pedal forces were similar for ES-LC (20.5±3.3 N) and VOL-LC (20.6±4.1 N). Mean peak lateral (outward) force in the leg restraints was higher in ES-LC (28.2±3.5 N) than in VOL-LC(21.7±2.5 N). These data suggest that unfavorable biomechanics, such as larger medio-lateral, shear and normal forces and larger within-cycle fluctuations, may increase energy use and thus contribute to the inefficiency of ES-LC.

Physical inactivity and substance abuse may lead to a greater likelihood for developing secondary medical complications in a rehabilitation population. Therefore, the purpose of this study was to develop an evaluation instrument and technique to determine the relationship among activity level, physical fitness, and substance abuse in a group of adults engaged in a vocational rehabilitation program. Forty-two subjects (15 females and 27 males) were recruited from a clinical vocational rehabilitation program for this study. Subjects completed three questionnaires: 1) Medication and Other Drug Survey, 2) Physical Activity Questionnaire, and 3) the Groningen Activity Restriction Scale (GARS). Subjects also performed a four battery fitness assessment protocol (PFI) consisting of grip strength, skinfold body composition analysis, locomotive function test, and modified cycle ergometry test. This battery was combined to provide an index of relative fitness, alpha coefficient 0.74. The questionnaires and PFI were developed or modified specifically for this study. Results indicated that PFI were different(p<0.05) for age (<30 vs >40) and race (whites vs nonwhites), 13.7 vs 10 and 12 vs 8.6, respectively. No differences were found for gender, education level, or marital status. No differences were found for gender, or age with respect to activity restriction (Cronbach's reliability = 0.98). Twenty-four individuals used cigarettes and forty used alcohol regularly. Thirteen individuals mixed alcohol and other illicit drugs. However, correlation of PFI and activity restriction by substance abuse was not significant (F=0.45). The results of this preliminary study suggest that the developed instruments have the ability to provide objective data relative to physical fitness, activity level, and substance abuse. Further research in this area needs to be performed to elucidate these relationships.

The effects of 24 weeks of daily chromium supplementation (400 μg Cr as picolinate) were investigated in a double-blind design on 40 collegiate swimmers (20 male and 20 female) during the course of a full competitive season. Testing was performed pre-, mid-, and post-supplementation for the following parameters: lean body mass, fat mass, and percent body fat. Twenty subjects (10 male and 10 female) were randomly placed into each of two groups, chromium picolineate (CP) or placebo (P). The volume and intensity of training were controlled for both groups. Body composition parameters were measured using standard hydrodensiometry procedures. Mean results (male and female) for pre- and post-supplementation indicated that the CP group significantly(p<0.05) increased lean mass (+3.3%), decreased fat mass (-4.6%), and decreased percent body fat (-6.43%), compared to the P group. Mean results for the comparison between pre- and mid-supplementation (12 wk) measurements with respect to the body composition parameters indicated slight changes(p>0.05). Females had a greater magnitude and rate of change for body fat percentage compared to males (-8.2% and -4.66%), possibly owing to their higher initial relative body fat percentage. The greatest rate of change for both males and females, in body composition parameters, occurred between weeks 12 and 24. From these data it appears that CP was effective in inducing changes in body composition for both female and male swimmers, after 12 wk. It is speculated that early body composition adaptations were more related to the changes in training frequency, intensity and duration, rather than CP supplementation. These data also suggest that the effectiveness of CP may require a longer supplementation period than is routinely used; and may be more effective when used in conjunction with higher intensity aerobic exercise, as performed in this study.

The original Therapeutic Alliances, Inc. model ERGYS functional electrical stimulation (FES) leg cycle ergometer (LCE) induces therapeutic exercise of the paralyzed quadriceps, hamstring and gluteal muscle groups of persons with spinal cord injury (SCI) to promote muscular and cardiopulmonary fitness. We modified this instrument in an effort to enhance physiologic response magnitudes. The purpose of this study was to compare peak metabolic and cardiopulmonary responses during stress testing with the original and an enhanced ERGYS FES-LCE. Modifications consisted of increasing max FES current output from 140 to 300 mA, adding the tibialis anterior and gastroc-soleus muscle groups, increasing the FES firing angle ranges by 55°, and utilizing an external flywheel resistance controller for immediate and continuous setting of load without stopping exercise to reprogram the system. Eight subjects with lower-limb paralysis due to SCI volunteered to participate. A continuous stress test protocol was used where the target pedal rate was 50 rpm. Exercise commenced at 0 load for 2 min, and power output (PO) was increased by 3.1 W (i.e., 1/16 kp) increments at 2-min intervals until fatigue caused rpm to drop to 35. At max PO, peak oxygen uptake (VO2), pulmonary ventilation (VE), heart rate (HR), stroke volume (SV), cardiac output (Q) and blood lactate concentration (LA) were determined. We found that max PO for the enhanced vs original ERGYS was similar. Lack of greater PO for the enhanced ERGYS was probably due to the fatiguing effects of the longer contraction duty cycle with wider firing angle ranges. However, the enhanced ERGYS elicited higher (p<.05) peak VO2(+16.1%), VE(+43.4%), HR (+25.3%), SV (+10.2%), Q (+36.2%) and LA (+52.3%). Greater peak metabolic and cardiopulmonary responses obtained via the incorporated modifications to the FES-LCE may permit greater muscular and cardiopulmonary training capability.

Changes in lower-limb muscle performance of 7 male subjects (mean age 37 yr± 14 and 12 yr ± 6 post-injury) with spinal cord injury (SCI) were evaluated following 6 wk of interval training (3x/wk) on anenhanced ERGYS functional electrical stimulation leg cycle ergometer(FES-LCE). FES-LCE modifications included: increasing max FES current output(140 to 300 mA), adding gastroc-soleus (GS) and tibialis anterior (TA) muscle groups, increasing the FES firing angle ranges (+55°), and using an external flywheel resistance controller. Prior to an following training, subjects underwent FES-induced isometric muscle performance testing of the GS, quadriceps (Q), hamstrings (H), gluteals (GL), and TA muscle groups (right side) on a Kin-Com II. Twenty contractions were induced by having FES current ramp from 0-300-0 mA over 24 s, each followed by a 5-s rest interval. Following FES-LCE training, mean peak torque increased for the GS (25.2 vs 34.5 N·m; p<0.05), Q (42.8 vs 44.5 N·m), and H(17.0 vs 19.5 N·m). Mean torques for the 20 contractions increased(p<0.05) for the GS (12.9 vs 19.6 N·m), Q (31.9 vs 39.2 N·m), and H (7.3 vs 9.8 N·m). No increases in performance were found for the GL and TA muscle groups. The peak torque generated per unit of FES current applied increased (p<0.05) for the GS (0.14 vs 0.22 N·m/mA), Q (0.31 vs 0.39 N·m/mA), H (0.07 vs 0.11 N·m/mA), and GL (0.15 vs 0.17 N·m/mA). These data suggest that 6 wk of enhanced FES-LCE interval training can elicit adaptations to improve peak torque, mean torque, and peak torque/current for the GS, Q, H, and GL muscle groups. Increased training intensity and duration, as well as reducing the GS co-contraction during TA stimulation may be required to elicit greater performance gains for the TA.