Traumatogenic factors affecting the knees of carpet installers

An ergonomics analysis of carpet installation tasks was performed. The purpose was to identify and quality potential sources of biomechanical trauma that may be responsible for the high rates of knee morbidity found by previous researchers among carpet layers. Nine carpet layers were studied either at an apartment building worksite or at a training school. Results from a job analysis indicated that workers spent approximatately 75% of their time in the kneeling position using a tool called a knee-kicker to stretch and install carpet. Awkward body postures were identified from films of workers installing carpets. At the moment of impact the knee is severely flexed, subtended angles were less than 60 degrees. To obtain measures of impact force on the knee, the kicker-tool was instrumented with a load cell. Workers who executed the hardest kicks with the tool produced impact peak forces that averaged 3019 newtons (N), which is equivalent to about four times body weight. Measures from an accelerometer attached to the worker's knee showed values in ecxess of 120 m/s², which are comparable to those found during vigorous running and jumping exercises. The results imply that repetitive impact of the knee joint from the use of the knee-kicker combined with knee flexion, kneeling and squatting may be responsible for the high level of occupational knee-morbidity found among carpet layers.     

Biomechanical evaluation of heavy tool-handling in two age groups of firemen

The biomechanical load of a rescue-clearing task (lifting a power saw from the floor up to the ceiling level) was evaluated with six older (47 ± 5 years) and seven younger firemen (32 ± 2 years). The mean dynamic compressive force at the L5/SI disc was 5998?N for the older subjects and 6392?N for the younger subjects. The peak torques for the back and knee extensions were about equal for the two groups of the subjects. The younger subjects had a significantly higher movement speed in the knee extension than the older subjects (89.1 ± 25.7 vs. 35.3±11.5°/, p<0.001). The results showed that lifting a power saw produced a high load on the musculoskeletal system, and that the load was not influenced by age.     

Cardiac frequency throughout a working shift in coal miners

Despite the ever-increasing mechanization of industrial activities, coal mining still remains a physically demanding occupation as it is not always possible to extensively mechanize the extraction process. To estimate the physical effort necessary to sustain coal mining activities in a poorly-mechanized mine, cardiac frequency (?/_c) was measured throughout the working shift with a Sport-Tester PE3000 (Polar Electro OY. Finland) in a representative sample of 73 Asturian miners engaged in a full spectrum of underground work. The mean ± SD of the overall?/_c values measured in miners working at the coal face (Group 1, 33 subjects, mean age 32·7 years, age range 21–48 years R was 106·5 ± 18·2 beats min^?1. In other miners (Group 2, 40 subjects, mean age 34·6 years, age range 23–48 years) corresponding figures were 1031 ±177 beats-min_?1 (p<0·05). Subjects' average working shift?_c Lbeats. Min^?1) was not related to age, measured (treadmill) VO₂ max nor VO₂ max.kg body weight^?1, while average working-shift? _c (%? _c max) was weakly related to age (r = 0·396, p<0·05), VO₂ max (r equals; 0·295, p < 0·05) and VO₂max.kg body weight^?1 (r= 0·352, p<0·05). Working-shift peak? _c (beats · min^?1) was negatively related to age (r = 0·334, p < 0·05). Our study has provided the distribution of the overall ? _c values likely to be found in subjects working in these poorly-mechanized mines. However, average working-shift ? _c differs considerably from subject to subject and is largely unpredictable.     

Maximal manual stretcher carriage: performance and recovery of male and female ambulance workers

The effects of a maximal duration stretcher carriage on heart rate (HR), lactate concentration, hand steadiness and hand-grip strength were studied up to 72 h post-exercise in 17 male and 15 female military ambulance personnel. Using both hands for transport, the participants walked on a treadmill ergometer at a speed of 4.5 km/h. Force measurements at the handlebars yielded mean loads of 245 N (25 kg) on each side. Each step on the treadmill induced additional force oscillations with peak forces up to 470 N corresponding to 130% (women) and 98% (men) of maximal voluntary contraction (MVC). In the males the maximal transport time was about twice the time in women (mean ± SD: 184 ± 51 s vs. 98 ± 34 s). These differences had no significant effect on HR and lactate values. The same applies to hand steadiness, which showed only a transient deterioration immediately after exercise. In contrast to these parameters, substantial differences were seen in hand-grip strength recovery. Immediately after exercise, maximal hand-grip strength decreased by 150 N (25% MVC) in the males vs. 50 N (14%) in the females. Irrespective of gender, individuals with larger hand-grip strength and longer carriage durations (range 120 s–280 s) showed the slowest strength recoveries (up to 72 h) as compared to 1 h of recovery in participants with short transport durations (range 27 s–120 s). These findings suggest that the increasing number of eccentric strains during uninterrupted stretcher carriage induces cumulative muscle damages that may require some days for complete recovery.     

DEPARTMENT OF SCIENTIFIC AND INDUSTRIAL RESEARCH: HUMAN SCIENCES COMMITTEE

Maximal power output during short term constant velocity cycling and vertical jumping from a force platform has been studied in five healthy young male subjects. From the measurements on the force platform the peak (instantaneous) power output (P), net impulse (I_N ), force (F₁ ). velocity of take-off(V_T ) and height of jump(h) were calculated. The corresponding values for power (H), force (F) and velocity (V) on the bicycle were obtained from analysis of the force-velocity relationship.

The results (mean ± S.D.) showed that on the force platform F₁ P, I_N, V_T and h were 1073± 167N, 2205±310W, 154±17Ns, 2·48+0·15ms^?1 and 31 +4cm. h was positively associated with both I_N (r= +0·77) and P (r = 0·67). The mean maximal power output for cycling was 854W(39%) greater than jumping and was achieved at a 271N (25%) increase in F and a reduction in V. Nevertheless they were closely related.

Platform P(W) = 717·6 + 0·483 bicycle H(W) r= +0·74

A comparison of linear and curvilinear (hyperbolic) analysis of the F/V bicycle data showed that the latter did not reduce the variance of observations and was not, therefore, statistically justifiable (Wilkie 1950). The mean intra-subject variations of P and H were 6·6%± 1·8 and 40%+1·2. The relative values of F and V at H were both found to be approximately 50% of their respective maximal values.

It was concluded that short term power output can be measured simply and accurately in man during the performance of two activities. Rotational movement of the legs as in cycling produces higher values of peak power output then vertically lifting body weight. For the achievement of peak power output in cycling, relative force and speed of movement must both correspond to approximately half of their respective maximal values.     

Ergonomics International

It was the purpose of this study to examine whether replacing long pants (P) with shorts (S) would reduce the heat stress of wearing firefighting protective clothing during exercise in a warm environment. Twenty-four Toronto Firefighters were allocated to one of four groups that performed heavy (H, 4.8?km·h^?1, 5% grade), moderate (M, 4.5?km·h^?1, 2.5% grade), light (L, 4.5?km·h^?1) or very light (VL, 2.5?km·h^?1) exercise while wearing their full protective ensemble and self-contained breathing apparatus. Participants performed a familiarization trial followed by two experimental trials at 35°C and 50% relative humidity wearing either P or S under their protective overpants. Replacing P with S had no impact on the rectal temperature (T_re) or heart rate response during heavy or moderate exercise where exposure times were less than 1?h (40.8?±?5.8 and 53.5?±?9.2?min for H and M, respectively while wearing P, and 43.5?±?5.3 and 54.2?±?8.4?min, respectively while wearing S). In contrast, as exposure times were extended during lighter exercise T_re was reduced by as much as 0.4°C after 80?min of exercise while wearing S. Exposure times were significantly increased from 65.8?±?9.6 and 83.5?±?11.6?min during?L and VL, respectively while wearing P to 73.3?±?8.4 and 97.0?±?12.5?min, respectively while wearing S. It was concluded that replacing P with S under the firefighting protective clothing reduced the heat stress associated with wearing the protective ensemble and extended exposure times approximately 10?–?15% during light exercise. However, during heavier exercise where exposure times were less than 1?h replacing P with S was of little benefit.     

Effect of friction and load on pinch force in a hand transfer task

The effect of friction and load on pinch force was studied in a simple hand transfer task using a repeated measures design and ten men. Subjects moved a container between two targets, 450?mm apart, at a slow, self-paced speed. The levels of mass in the container were set at 0·8, 2·5 and 4·2?kg (7·5, 24·5 and 41·5?N respectively). The handle materials were sandpaper and smooth aluminium. Applied pinch force was measured via a strain gauge mounted in a specially-designed handle attached to the container. Dependent variables were peak and ‘steady-state’ pinch force. The main and interaction effects of load and friction were significant. The friction effect was significant only for the highest load which, on average, elicited peak pinch forces of 16-70% of maximum voluntary force. This suggests that these men were not sensitive to friction effects at the lower loads. Results suggest that the use of tool handle friction enhancements may reduce required pinch forces for objects requiring upwards of 50% or more of maximum pinch strength     

Cooling of motorcyclists in various clothing during winter in Britain

Abstract

Skin and ear-canal temperatures of seven volunteer motorcyclists have been measured during control periods and during rides of up to 161km at air temperatures below 10°C. While wearing their own clothing in air temperatures between 2·6 and 10 C the riders showed changes in heat storage of - 438 to - 1611 Wm^?2. The average of the three lowest temperatures (°C) recorded from selected sites from different subjects (and the means of the laboratory control values from all seven subjects + standard errors) were: foot, 14·7 (30·6 ± 0·93); shin, 21·4 (32·2± 0·40); thigh, 17·8 (31·8± 0·36); abdomen and chest, 25·3(34·7 ± 0·26); forearm, 28·8 (33·8±0·19; hand, 15·5 (30·8±0·58); ear canal, 36·1 (37·2 ± 0·7). The rate at which riders' feet cooled was not closely related to the rates their bodies cooled. Even when there was no body cooling, their feet cooled by at least 3°C hour^?1, while riding. The thickness of motorcycle clothing and its wind-proofing are both important in preventing cooling. Zip fasteners need special protection beyond that needed merely to keep out rain.     

Effect of different handgrip angles on work distribution during hand cycling at submaximal power levels

The effect of different handle angles on work distribution during hand cycling was determined. Able-bodied subjects performed hand cycling at 20% of maximum power level (mean (SD) power level: 90.0 (25.8) W) at a cadence of 70 rpm using handle angles of ±30°, ±15° and 0°. The handle angle had a significant effect on work during the pull down (p < 0.001) and lift up (p = 0.005) sector, whereby the highest work was performed with handle angles of +30° and ?15° respectively. The cycle sector had a significant effect on work (p < 0.001) and significantly (p = 0.002) higher work was performed in the pull down sector (25% higher than mean work over one cycle) as compared to the lift up sector (30% lower than mean work over one cycle). Therefore, a fixed handle angle of +30° is suggested to be optimal for power generation. The results of this study help to optimise the handbike–user interface. A more pronated handle angle compared to the one conventionally used was found to improve the performance of hand cycling and thereby the mobility of disabled people.     

The Effect of Posture on the Running Speed of Skiing

Abstract

These experiments were performed at the Syowa Station in Antarctica (69°00'S, 39° 35'E) where a straight ski course was constructed (length 100m. gradient 12°). The conditions were as follows; wind velocity: 0-0·5ms^?1, temperature: ? 25°C, snow temperature: ?29·5°C.snow density: 0·309 gcm^?3. Running speed was measured by a coil-magnet system. The subject with a small magnet fixed on one leg ran closely down past the coils placed every 5m along the course. Two healthy members of the Japanese Antarctic Research Expedition who were well-trained skiers acted as subjects. Running speed was measured in three different postural conditions (a) standing, (b) egg-shaped, (c) starting in the egg-shaped posture and then standing erect in the latter half of the course. Velocity was measured throughout the course and the following results were obtained: velocities at the final section of the coils, which were placed 65m from the start point, were as follows for each postural condition: Subject KW; (a) standing, 7·6ms^?1 (b) egg-shaped, 8·6ms^?1 (c) egg-shaped followed by standing erect, 8·2ms^?1. Subject B; (a) 7·8ms^?1, (b) 8·9ms^?1, (c) 8·4ms^?1. The friction between the ski and snow was calculated as about 0·13 for all conditions. It was concluded that postural difference may have a considerable and clear-cut effect on running speed even when the skiing speed is rather low.     

John G. Fox (1931-2004)

The effectiveness of intermittent, microclimate cooling for men who worked in US Army chemical protective clothing (modified mission-oriented protective posture level 3; MOPP 3) was examined. The hypothesis was that intermittent cooling on a 2 min on–off schedule using a liquid cooling garment (LCG) covering 72% of the body surface area would reduce heat strain comparably to constant cooling. Four male subjects completed three experiments at 30°C, 30% relative humidity wearing the LCG under the MOPP 3 during 80 min of treadmill walking at 224 ± 5 W · m^?2. Water temperature to the LCG was held constant at 21°C. The experiments were; 1) constant cooling (CC); 2) intermittent cooling at 2-min intervals (IC); 3) no cooling (NC). Core temperature increased (1.6 ± 0.2°C) in NC, which was greater than IC (0.5 ± 0.2°C) and CC (0.5 ± 0.3°C) ( p < 0.05). Mean skin temperature was higher during NC (36.1 ± 0.4°C) than IC (33.7 ± 0.6°C) and CC (32.6 ± 0.6°C) and mean skin temperature was higher during IC than CC ( p < 0.05). Mean heart rate during NC (139 ± 9 b · min^?1) was greater than IC (110 ± 10 b · min^?1) and CC (107 ± 9 b · min^?1) ( p < 0.05). Cooling by conduction (K) during NC (94 ± 4 W · m^?2) was lower than IC (142 ± 7 W · m^?2) and CC (146 ± 4 W · m^?2) ( p < 0.05). These findings suggest that IC provided a favourable skin to LCG gradient for heat dissipation by conduction and reduced heat strain comparable to CC during exercise-heat stress in chemical protective clothing.     

Impact of fluid replacement on heat storage while wearing protective clothing

This study used partitional calorimetry to determine the influence of fluid replacement on heat storage during uncompensable heat stress. Eight males performed either light (L; level treadmill walking at 0.97 m·s^-1 (3.5 km·h^-1) or heavy (H; 1.33 m·s^-1 (4.8 km·h^-1) at a 4% grade) exercise at 40°C and 30% relative humidity while wearing nuclear, biological and chemical (NBC) protective clothing. Subjects received either no fluid (NF), or 200 or 250 ml of fluid (F) as warm water at ~ 35°C immediately before and every 15 min during the L and H trials respectively. Similar reductions in heart rate were observed at both metabolic rates with F but rectal temperature responses were not different between F and NF. Tolerance time was extended during L/F (106.5±22.1 min) compared with L/NF (93.1±20.8 min) but fluid replacement had no influence during H (59.8±9.5 min and 58.3±11.1 min for F and NF respectively). Fluid replacement also had no effect on the rate of heat storage during L (108.2±20.6 W·m^-2 and 111.0±22.6 W·m^-2 for F and NF respectively) and H (172.5±11.5 W·m^-2 and 182.1±15.8 W·m^-2 for F and NF respectively). However, heat storage expressed per unit of mass was significantly increased during L/F (18.5±4.0 kJ·kg^-1) compared with the other trials (16.3±4.8 kJ·kg^-1, 16.6±3.0 kJ·kg^-1 and 16.7±4.0 kJ·kg^-1 for L/NF, H/F and H/NF respectively). It was concluded that fluid replacement does not alter the rate of heat storage during uncompensable heat stress but does increase the heat storage capacity during light exercise when tolerance times are > 60 min.     

The effect of aerodynamic handlebars on oxygen consumption while cycling at a constant speed

Abstract

In this study, the oxygen consumption ([Vdot]O₂) of bicycling was measured at a fixed speed (40 km·h^?1on level terrain, with normal and aerodynamic handlebars using a Douglas bag collection system. Eleven elite (USCF category I or 2) men cyclists age 24 to 40 years (X¯=28·5, SD±4·6) performed four consecutive (two with each bar in alternating order) steady state rides at 40 km· h^?1over a 4 km flat course (same direction each trial). Expired gases were collected in a 1501 Douglas bag attached to a following vehicle during the last 45 s (approx. 0·5 km) of each trial. A repeated measures analysis of variance revealed a significant (p<0·02) handlebar effect. Specifically, [Vdot]O₂was 2% lower under the aerodynamic handlebar treatment (X¯=4·26, SD±0·36 1 min^?1when compared with that of the normal handlebar treatment (X¯=4·34, SD±0·35 1 min^?1The results of this study demonstrate that the reported aerodynamic advantage of the aerodynamic handlebars produces a small but significant reduction in the [Vdot]O₂of bicycling at 40 km·h^?1     

Lift performance and lumbar loading in standing and seated lifts

This study investigated the effect of posture on lifting performance. Twenty-three male soldiers lifted a loaded box onto a platform in standing and seated postures to determine their maximum lift capacity and maximum acceptable lift. Lift performance, trunk kinematics, lumbar loads, anthropometric and strength data were recorded. There was a significant main effect for lift effort but not for posture or the interaction. Effect sizes showed that lumbar compression forces did not differ between postures at lift initiation (Standing 5566.2?±?627.8 N; Seated 5584.0?±?16.0) but were higher in the standing posture (4045.7?±?408.3 N) when compared with the seated posture (3655.8?±?225.7 N) at lift completion. Anterior shear forces were higher in the standing posture at both lift initiation (Standing 519.4?±?104.4 N; Seated 224.2?±?9.4 N) and completion (Standing 183.3?±?62.5 N; Seated 71.0?±?24.2 N) and may have been a result of increased trunk flexion and a larger horizontal distance of the mass from the L5-S1 joint.

Practitioner Summary: Differences between lift performance and lumbar forces in standing and seated lifts are unclear. Using a with-in subjects repeated measures design, we found no difference in lifted mass or lumbar compression force at lift initiation between standing and seated lifts.     

Characterization of a capacitive tactile shear sensor for application in robotic and upper limb prostheses

This paper presents the characterization of a novel tactile sensor designed to measure shear forces. The sensor design is targeted for use in robotic and prosthetic hands, where haptic feedback or ability to detect shear forces associated with slip are critical. The presented sensor utilizes the principle of differential capacitance to measure the mechanical deflection of the sensor element. The dynamic range of the sensor can be varied by encapsulating the sensor terminal within silicone of varying hardness. The design features ease of mass production, low per-unit-cost, novel overload protection and low wire count, while still preserving the ability to achieve reasonable spatial resolutions and array densities. Mathematical and COMSOL multiphysics models of the sensor are presented, in addition to results from practical experiments. Sensors with a full scale displacement range of ±0.525 mm were produced and the differential capacitance was measured. Shear force transduction was characterized over the range of 0 N–4 N with the sense terminal encapsulated by silicone with a shore A hardness of 20. The effect of elastomer hardness on the sensor's dynamic range was analyzed. The differential capacitance, when measured at each fixed interval, was found experimentally to have a maximum standard deviation of 4.28e?16 F over a ±2 N range. A maximum standard deviation of 1.35e?15 F was measured across characterized full scale sensor range of ±4 N. The sensor design has a sensitivity of 1.967 fF/N of applied force and the sensor output was found to be approximately linear. The coefficient of determination, r², was found to be 0.941.     

Biomechanical risk assessment during field loading of hydraulic stretchers into ambulances

The process of loading a stretcher into an ambulance is known to cause a high incidence of back injuries among paramedics. This study aimed to assess the forces at L5/S1 during real-life stretcher loading activities and to determine the variables that contribute significantly to these forces. Analyses involved 58 paramedics (111 shifts) and 175 stretcher loading activities. Estimates of compression and shear forces at L5/S1 were calculated using the 3DSSPP program. Seventy-one percent of loading activities exceeded the safe loading level of 3.4 kN compression force at L5/S1 (mean: 3.9 kN, min–max: 2.1–7.0 kN). About 92% of the variance can be predicted from a combination of several variables, notably hand load (mean: 0.72 kN/number of paramedics) and back sagittal flexion (mean: 32°). Recommendations to reduce the risk of back injuries are proposed with regard to stretcher and ambulance loading design as well as training in stretcher lifting for paramedics.Relevance to the industryThe results of this study suggest that ambulance stretcher manufacturers should make ergonomic design changes to reduce the physical strain on paramedics’ backs during the process of loading a stretcher into an ambulance. Other preventive measures (e.g., training) must be formulated and applied to reduce the risk of back musculoskeletal disorders during the loading of stretcher patients. For instance, training should focus on back posture, teamwork and equipment/patient positioning on stretchers.     

Ergonomics diary

Physiological, perceptual and physical responses to a typical circuit weight-training (CWT) regimen were recorded in two studies. The aims were to assess the intensity of exercise during CWT; and to determine whether physical responses as evaluated by spinal shrinkage were related to physiological and perceptual responses to CWT. In the first study (n = 10) heart rate (HR), oxygen consumption (VO), ventilation (VE), blood lactate (La) and perceived exertion (RPE) were measured in response to CWT. Mean ( ± SD) time to complete three circuits of CWT was 17.8 (± 1-4) min. The HR max, VO₂max and peak La, measured first during an incremental treadmill test, were 195 (±13) beats.min ^?159-7 (±4-8) ml.kg^?1.min^?1 and 14-3 (±3-5) mM respectively. Mean HR and vO₂ during CWT were 69% and 50% of the respective maximal values. The HR-VO₂ ratio observed on the treadmill was elevated during CWT, with VO₂ being lowered relative to HR. Mean VE and La values were 52-7 (± 14-5) l.min^?1 and 6-9 ( ± 3-6) mM. The effect of the same CWT regimen on spinal loading as indicated by change in stature (shrinkage) was investigated in a second study (n = 8). The mean ( ± SD) time taken to complete the circuit was 17-4 ( ± 1-3) min. Mean shrinkage due to CWT (2-5 ± 1 -5?mm) was unrelated to the time taken to complete the circuits, to HR, RPE or to low back pain ratings (p > 0-05). Observations suggest that CWT as represented in these studies engages anaerobic as well as aerobic mechanisms but the exercise intensity may not provide sufficient stimulation for aerobic training. The physical load on the spine indicated by spinal shrinkage was not related to the physiological or perceptual strain.     

Evaluation of a knee-kicker bumper design for reducing knee morbidity among carpet layers

Carpet layers have a high prevalence of occupational knee morbidity. One of the main causes is that they need to frequently 'kick' the bumper on the rear end of the knee kicker with one knee when laying a carpet. Considering the bumper's marked effects on kicking force transmission and safety, this study aims to improve the design of the knee-kicker bumper by reducing the risk factors. An improved pendulum-type impact-testing platform was designed as an evaluative apparatus, with the impulse and the coefficient of restitution serving as evaluative criteria. The newly developed bumper has improved firmness from drilled blind holes and an increase in effective forward force of 15%-138%, which implies lower operational demands and a lighter knee burden (i.e., less kicking energy results in the same work efficiency), and a softer contact surface that enhances operating comfort. The newly designed kicker was positively reviewed by subjects.     

Study of PBL dynamics over northern plains in fixing stack height of a super thermal power station

The Planetary Boundary Layer plays an important role in air pollution meteorology and in fixing the Stack height of major air-polluting industries, including the super thermal power plants. In India a super thermal power plant is being set up at Yamunanagar (30·1° N, 77·33 ° E) and it has been studied using an acoustic sounder with a stack height of 220?m which would be the optimum height to keep the physical stack above surface based inversions for 80 per cent of the time and the elevated inversions for 50 per cent of time above. However, the hot plume rise would inject any pollutants above the surface based inversions for 95 per cent of the time     

Influence of two different modes of resistance training in female subjects

In resistance training, it has been empirically accepted that muscle hypertrophy is developed by low intensity and high volume training, while muscle strength and power are developed by high intensity and low volume training. The purpose of the present study was to investigate the influence of two different modes of resistance training on isokinetic strength and muscle cross-sect tonal area (CSA) in females. Eleven females, who had no experience in resistance training, participated in this study and were randomly divided into two groups. The former consisted of 4-5 sets of 15-20 RM (repetition maximum) with sufficient rest between sets (Group H), while the latter consisted of 8-9 sets of 4-6 RM with 90s of rest between sets (Group S). The former was assumed to be appropriate for muscle hypertrophy and the latter muscle strength, respectively. All subjects completed isotonic knee extension exercise three times a week for 8 weeks. Measurements were made on quadriceps muscle cross-sectional area (CSA) and isokinetic torques at 0, 60, 180, and 300°/s before training, at the fifth week and the end of training period. Muscle CSA was defined as the sum of CSA measured at 30, 50 and 70% of femur length, After training, muscle CSA had significantly increased in both groups: 3·3 ± 0·7% (p <·05) for group H and 3·6 ± 1·1% (p < ·05) for group S, respectively. While the changes in isokinetic torque were 43·4 ± 47·5% (p <·05) for group H and 27·4 ± 31·3% (p <·05) for group S, respectively. In both groups the percentage changes of the isokinetic strength were significantly higher than those of the CSA. No significant difference in these variables were found between the two groups. These results suggest that during the early phase of resistance training two different modes of resistance training may have similar effects on muscle CSA and isokinetic strength in untrained females.