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At least 19 recordsLinked to original sources

PubMed1983

Life cycle efficiency of beef production: II. Relationship of cow efficiency ratios to traits of the dam and progeny weaned.

Several measures of life cycle cow efficiency were calculated using weights and individual feed consumptions recorded on 160 dams of beef, dairy and beef X dairy breeding and their progeny. Ratios of output to input were used to estimate efficiency, where outputs included weaning weights of progeny plus salvage value of the dam and inputs included creep feed consumed by progeny plus feed consumed by the dam over her entire lifetime. In one approach to estimating efficiency, inputs and outputs were weighted by probabilities that were a function of the cow herd age distribution and percentage calf crop in a theoretical herd. The second approach to estimating cow efficiency involved dividing the sum of the weights by the sum of the feed consumption values, with all pieces of information being given equal weighting. Relationships among efficiency estimates and various traits of dams and progeny were examined. Weights, heights, and weight:height ratios of dams at 240 d of age were not correlated significantly with subsequent efficiency of calf production, indicating that indirect selection for lifetime cow efficiency at an early age based on these traits would be ineffective. However, females exhibiting more efficient weight gains from 240 d to first calving tended to become more efficient dams. Correlations of efficiency with weight of dam at calving and at weaning were negative and generally highly significant. Height at withers was negatively related to efficiency. Ratio of weight to height indicated that fatter dams generally were less efficient. The effect of milk production on efficiency depended upon the breed combinations involved. Dams calving for the first time at an early age and continuing to calve at short intervals were superior in efficiency. Weaning rate was closely related to life cycle efficiency. Large negative correlations between efficiency and feed consumption of dams were observed, while correlations of efficiency with progeny weights and feed consumptions in individual parities tended to be positive though nonsignificant. However, correlations of efficiency with accumulative progeny weights and feed consumptions generally were significant.

Animals↗

PubMed1983

Life cycle efficiency of beef production: I. Cow efficiency ratios for progeny weaned.

Weights and individual feed consumption collected on 160 beef, dairy and beef X dairy dams and their progeny were used to estimate several measures of lifetime cow efficiency. Dams were fed either a high or a low energy diet. Efficiency was expressed as the ratio of outputs to inputs. Outputs included progeny weaning weights plus cow salvage weight, and inputs were progeny creep feed consumption plus the dam's lifetime feed consumption. In the first approach, life cycle cow efficiency was estimated by expressing weight output as a ratio to feed inputs when weights and feed consumptions were weighted by their probabilities; probabilities were a function of age distribution and percentage calf crop in a theoretical herd consisting of 100 cows and 20 yearling replacement heifers. In the second approach, actual lifetime cow efficiency was estimated by expressing weight outputs as a ratio to feed inputs when all components were weighted equally. Both approaches included efficiency estimates calculated with and without cow salvage value. Dams receiving low energy diets generally had lifetime efficiencies equal or superior to those fed high energy diets in spite of older ages at calving. Dams on the high energy diet had greater salvage value, but did not wean calves of sufficient additional size to offset their own increased metabolizable energy (ME) intake. Dam breeds and breed crosses of smaller size tended to be more efficient than those of large size, demonstrating the effectiveness of mating small dams to large sire breeds for improving cow efficiency. Breeds calving at later ages were less efficient. Efficiency ratios improved as number of progeny weaned increased.

Age Factors↗

PubMed1996

Mechanical efficiency and efficiency of storage and release of series elastic energy in skeletal muscle during stretch-shorten cycles.

The mechanical energy exchanges between components of a muscle-tendon complex, i.e. the contractile element (CE) and the series elastic element (SEE), and the environment during stretch-shorten cycles were examined. The efficiency of the storage and release of series elastic energy (SEE efficiency) and the overall mechanical efficiency of the rat gastrocnemius muscle (N = 5) were determined for a range of stretch-shorten contractions. SEE efficiency was defined as elastic energy released to the environment divided by external work done upon the muscle-tendon complex plus internal work exchange from the CE to the SEE. Mechanical efficiency is external work done by the muscle-tendon complex divided by the external work done upon the muscle-tendon complex plus work done by the CE. All stretch-shorten cycles were performed with a movement amplitude of 3mm (6.7% strain). Cycle frequency, duty factor and the onset of stimulation were altered for the different cycles. SEE efficiency varied from 0.02 to 0.85, mechanical efficiency from 0.43 t 0.92. SEE efficiency depended on the timing of stimulation and net muscle power in different ways. Mechanical efficiency was much more closely correlated with net power. The timing of muscle relaxation was crucial for the effective release of elastic energy. Simulated in vivo contractions indicated that during rat locomotion the gastrocnemius may have a role other than that of effectively storing elastic energy and generating work. Computer simulations showed that the amount of series elastic compliance can affect the internal energetics of a muscle contraction strongly without changing the muscle force generation dramatically.

Animals↗

PubMed2004

Slow skeletal muscles of the mouse have greater initial efficiency than fast muscles but the same net efficiency.

The aim of this study was to determine whether the net efficiency of mammalian muscles depends on muscle fibre type. Experiments were performed in vitro (35 degrees C) using bundles of muscle fibres from the slow-twitch soleus and fast-twitch extensor digitorum longus (EDL) muscles of the mouse. The contraction protocol consisted of 10 brief contractions, with a cyclic length change in each contraction cycle. Work output and heat production were measured and enthalpy output (work + heat) was used as the index of energy expenditure. Initial efficiency was defined as the ratio of work output to enthalpy output during the first 1 s of activity. Net efficiency was defined as the ratio of the total work produced in all the contractions to the total, suprabasal enthalpy produced in response to the contraction series, i.e. net efficiency incorporates both initial and recovery metabolism. Initial efficiency was greater in soleus (30 +/- 1%; n=6) than EDL (23 +/- 1%; n=6) but there was no difference in net efficiency between the two muscles (12.6 +/- 0.7% for soleus and 11.7 +/- 0.5% for EDL). Therefore, more recovery heat was produced per unit of initial energy expenditure in soleus than EDL. The calculated efficiency of oxidative phosphorylation was lower in soleus than EDL. The difference in recovery metabolism between soleus and EDL is unlikely to be due to effects of changes in intracellular pH on the enthalpy change associated with PCr hydrolysis. It is suggested that the functionally important specialization of slow-twitch muscle is its low rate of energy use rather than high efficiency.

Animals↗

PubMed1995

Lack of an effect of the efficiency of RNA 3'-end formation on the efficiency of removal of either the final or the penultimate intron in intact cells.

Evidence exists from studies using intact cells that intron removal can be influenced by the reactivity of upstream and downstream splice sites and that cleavage and polyadenylation can be influenced by the reactivity of upstream splice sites. These results indicate that sequences within 3'-terminal introns can function in the removal of upstream introns as well as the formation of RNA 3' ends. Evidence from studies using intact cells for an influence of RNA 3'-end formation on intron removal is lacking. We report here that mutations within polyadenylation sequences that either decrease or increase the efficiency of RNA 3'-end formation have no effect on the efficiencies with which either the 3'-terminal or the penultimate intron is removed by splicing. Northern (RNA) blot hybridization, RNase mapping, and an assay that couples reverse transcription and PCR were used to analyze the effects of deletions and a substitution of the polyadenylation sequences within the human gene for triosephosphate isomerase (TPI). TPI pre-mRNA harbors six introns that are constitutively removed by splicing. Relative to normal levels, each of the deletions was found to reduce the nuclear and cytoplasmic levels of TPI mRNA, increase the nuclear level of unprocessed RNA 3' ends, and decrease the nuclear level of processed RNA 3' ends. The simplest interpretation of these data indicates that (i) the rate of 3'-end formation normally limits the amount of mRNA produced and (ii) the deletions decrease and the substitution increases the efficiency of RNA 3'-end formation. While each of the deletions and the substitution altered the absolute levels of intron 6-containing, intron 5-containing, intron 6-free, and intron 5-free RNAs, in no case was there an abnormal ratio of intron-containing to intron-free RNA for either intron. Therefore, at least for TPI RNA, while the efficiency of removal of the 3'-terminal intron influences the efficiency of removal of either the 3'-end formation, the efficiency of RNA 3'-end formation does not influence the efficiency of removal of either the 3'-terminal or penultimate intron. The dependence of TPI RNA 3'-end formation on splicing may reflect the suboptimal strengths of the corresponding regulatory sequences and may function to ensure that TPI pre-mRNA is not released from the chromatin template until it has formed a complex with spliceosomes. If so, then the independence of TPI RNA splicing on 3'-end formation may be rationalized by the lack of a comparable function.

Animals↗

PubMed2003

The effect of activity-based financing on hospital efficiency: a panel data analysis of DEA efficiency scores 1992-2000.

Activity-based financing (ABF) was implemented in the Norwegian hospital sector from 1 July 1997. A fraction of the block grant from the state to the county councils has been replaced by a matching grant depending upon the number and composition of hospital treatments. As a result of the reform, the majority of county councils have introduced activity-based contracts with their hospitals. This paper studies the effect of activity-based funding on hospital efficiency. We predict that hospital efficiency will increase because the benefit from cost-reducing efforts in terms of number of treated patients is increased under ABF as compared with global budgets. The prediction is tested using a panel data set from the period 1992-2000. Efficiency indicators are estimated by means of data envelopment analysis (DEA) with multiple inputs and outputs. Using a variety of econometric methods, we find that the introduction of ABF has improved efficiency when measured as technical efficiency according to DEA analysis. The result is less uniform with respect to the effect on cost-efficiency.

Cost Allocation↗

PubMed1986

The efficiencies of the component steps of oxidative phosphorylation. II. Experimental determination of the efficiencies in mitochondria and examination of the equivalence of membrane potential and pH gradient in phosphorylation.

In the accompanying article (T.E. Gunter and B.D. Jensen, 1986 Arch. Biochem. Biophys. 248, 289-304), a method is described for measuring the efficiencies of individual steps of the process of oxidative phosphorylation. The results of applying this method to the case of state 3 phosphorylation in rat liver mitochondria are reported here. The rate of energy use (or power use) at the gradient generation, leakage, and phosphorylation steps are reported as efficiencies and energy use factors in tabular form. The limits of the degrees of coupling of the gradient generation and phosphorylation steps are also determined and under the current conditions of measurement these degrees of coupling are found to be quite close to unity. The data can be used to show that the only sets of the stoichiometric parameters noH (the charge/2e- ratio in this case from succinate to oxygen), nPH (the H+/ATP ratio), and nTH (number of protons translocated during substrate-product transport) which are simultaneously consistent with both the laws of thermodynamics and with the current data are 8, 3, 1, and 6, 3, 0. The The efficiency of the phosphorylation step which is independent of noH and nTH averages 80% for the control data analyzed. If noH is 8 (succinate to oxygen), the average value of the efficiency of generation of the electrochemical proton gradient is approximately 91 percent. Since very little power (energy) would then be left over to be coupled in parallel to phosphorylation through some other means of coupling, this would place the electrochemical proton gradient in the direct path of power flow and identify it as "an" intermediate in the process. This would suggest that any other intermediate should be considered as being "in series" with the electrochemical proton gradient. The agents butyrate and propionate have been employed to permit investigation over a range of pH gradient and membrane potential. Both butyrate and propionate decrease the efficiency of generation of the electrochemical proton gradient and increase proton leakage. In addition, butyrate activates electron transport whereas propionate inhibits it. By using butyrate to modify the values of pH gradient and membrane potential, it can be shown that the ratio of the efficiency with which the pH gradient is used in phosphorylation to that with which the membrane potential is used is 1.08 +/- 0.38.

Adenosine Diphosphate↗

PubMed2002

Development of safe and efficient novel nonviral gene transfer using ultrasound: enhancement of transfection efficiency of naked plasmid DNA in skeletal muscle.

Although clinical trials of stimulation of angiogenesis by transfection of angiogenic growth factors using naked plasmid DNA or adenoviral vector have been successful, there are still unresolved problems for human gene therapy such as low transfection efficiency and safety. From this viewpoint, it is necessary to develop safe and efficient novel nonviral gene transfer methods. As therapeutic ultrasound induces cell membrane permeabilization, ultrasound irradiation might increase the transfection efficiency of naked plasmid DNA into skeletal muscle. Thus, we examined the transfection efficiency of naked plasmid DNA using ultrasound irradiation with echo contrast microbubble (Optison) in vitro and in vivo experiments. First, we examined the feasibility of ultrasound-mediated transfection of naked plasmid DNA into skeletal muscle cells. Luciferase plasmid mixed with or without Optison was transfected into cultured human skeletal muscle cells using ultrasound (1 MHz; 0.4 W(2)) for 30 s. Interestingly, luciferase activity was markedly increased in cells treated with Optison, while little luciferase activity could be detected without Optison (P < 0.01). Electron microscopy demonstrated the transient formation of holes (less than 5 microM) in the cell surface, which could possibly explain the rapid migration of the transgene into the cells. Next, we studied the in vivo transfection efficiency of naked plasmid DNA using ultrasound with Optison into skeletal muscle. Two days after transfection, luciferase activity in skeletal muscle transfected with Optison using ultrasound was significantly increased about 10-fold as compared with plasmid alone. Successful transfection was also confirmed by beta-galactosidase staining. Finally, we examined the feasibility of therapeutic angiogenesis using naked hepatocyte growth factor (HGF) plasmid in a rabbit ischemia model using the ultrasound-Optison method. Five weeks after transfection, the angiographic score and the number of capillary density in rabbits transfected with Optison using ultrasound was significantly increased as compared with HGF plasmid alone (P < 0.01), accompanied by a significant increase in blood flow and blood pressure ratio (P < 0.01). Overall, the ultrasound transfection method with Optison enhanced the transfection efficiency of naked plasmid DNA in vivo as well as in vitro. Transfection of HGF plasmid by the ultrasound-Optison method could be useful for safe clinical gene therapy to treat peripheral arterial disease without a viral vector system.

Animals↗

PubMed2003

[Interrelationship between water use efficiency and nitrogen use efficiency of different wheat evolution materials].

A field micro-plot experiment on the interrelationship between water use efficiency and nitrogen use efficiency of different wheat evolution materials at the whole plant level showed that both water and nitrogen use efficiency increased gradually during the long evolution process from diploid to hexaploid. The water use efficiency was positively related with nitrogen use efficiency across nine evolution materials excluding French S. cereals, suggesting that the high nitrogen use efficiency of French S. cereals might be related with physiological mechanisms other than WUE.

Biological Evolution↗

PubMed1991

99Tcm-exametazime-labelled leucocytes: effect of volume and concentration of exametazime on labelling efficiency, and clinical protocol for high efficiency multi-dose radiolabelling.

We have investigated the effect of volume and concentration of exametazime on the labelling efficiency of 99Tcm-exametazime-labelled leucocytes. The first study examined the effect of varying the volume of exametazine solution whilst the concentration remained constant. A vial of Ceretec (Amersham Ltd plc) was reconstituted with sodium chloride injection BP. Aliquots of 0.25-2.0 ml were removed, added to sodium pertechnetate injection BP and incubated with 2 x 10(7)-5 x 10(7) leucocytes from 25 ml blood. The labelling efficiency decreased from 65 +/- 10% S.D. (0.25 ml) to 45 +/- 8% (2.0 ml) (n = 4). In a second study different concentrations of exametazime solution were used whilst the volume remained constant. A vial of Ceretec was reconstituted with sodium chloride injection BP. Aliquots of 25-200 micrograms were removed, made up to a fixed volume of 0.6 ml, added to pertechnetate and incubated with the plug of leucocytes as before. The labelling efficiency decreased as the concentration of ligand decreased. Thus for 200 micrograms/0.6 ml the labelling efficiency was 64 +/- 5% and for 25 micrograms/0.6 ml the labelling efficiency was 43 +/- 18% (n = 4). Clinical studies were performed using 50 ml blood from patients with a wide range of inflammatory disorders including inflammatory bowel disease, abdominal abscess and vasculitis. The concentration of ligand used was 83 micrograms/0.25 ml. The labelling efficiency was found to be 82 +/- 7% (n = 36).

Butanones↗

PubMed1983

Seeding efficiency, plating efficiency, and population doublings of human skin fibroblastlike cells: results of replicate testing.

Using skin fibroblastlike cells from 10 healthy volunteers, 12 to 54 yr old, we measured, in replicates, seeding efficiency (SE), plating efficiency (PE), and population doublings (PD) during 2 wk of growth and the cumulative replicative life span (CRLS). We determined the effects of donor age and of in vitro cell age on the test results and test precision. We found that (a) On the average, SE was 82% +/- 24 SD, PE was 12% +/- 9 SD, PD was 7.3 doublings +/- 2.5 SD, and CRLS was 31.1 doublings +/- 9.6 SD. (b) Plating efficiency and PD correlated well with each other and with CRLS whereas SE did not correlate with PE, PD, or CRLS. (c) Plating efficiency and PD were affected negatively by increasing passage levels and by donor ages, but the influence of age was evident only for cells from early passages. Seeding efficiency was not affected by either of the two variables. (d) Variations in PD from early passages explained half of the donor-to-donor variation in CRLS whereas PD from later passages had little or no predictive power. (e) Of the two short term tests, PD had better precision than PE. For replicate runs with cells from early passages the coefficient of variation was 44% for PE and 15% for PD. The results show that PD for cells from early passages in mass culture give rapid results, which express the in vitro replicating potential of cells from different donors with greater precision than do measurements of CRLS.

Adolescent↗

PubMed1973

Integration efficiency in DNA-induced transformation of Pneumococcus. II. Genetic studies of mutant integrating all the markers with a high efficiency.

Transformation of the pneumococcus mutant 401 by DNA's bearing the standard reference marker and several other markers belonging to two unlinked loci has shown that differences in the integration efficiencies of these markers were considerably reduced in this strain compared to the wild-type strain Cl(3). The sensitivities of mutant 401 to ultraviolet light and to X-ray irradiation are the same as those of Cl(3). However, in 401 all the markers tested are more resistant to inactivation as shown by transformation of 401 and Cl(3) by ultraviolet-irradiated DNA. The increase in resistance is greater for low efficiency (LE) markers than for high efficiency (HE) markers.-The decreased discrimination between LE and HE markers in strain 401 is not due to a mechanism related to modification of markers in the transforming DNA by the recipient cells, nor are the proteins inducing competence of the cells responsible for the differences in the integration efficiencies of various markers.-Genetic studies of the fate of recombinants as well as the measure of the amount of DNA taken up have shown that all the markers are integrated in strain 401 by the same recombination process, that specific to high efficiency markers.

Aminopterin↗

PubMed2005

Polarization-dependent diffraction efficiency of a photorefractive volume grating and suppression of this efficiency.

In terms of refractive-index ellipsoid of a uniaxial crystal, the relationship between the diffraction efficiency of a volume grating and the polarization state of a readout beam is theoretically analyzed. The direction of a refractive light beam and the corresponding refractive-index modulation will both be changed by a variation of the polarization state. In the polarization state of the readout beam, which may lead to a strong variation in the diffraction efficiency of the volume grating. This kind of polarization-dependent diffraction efficiency of a volume grating in an anisotropic crystal is extremely disadvantageous for some applications. A method to suppress the polarization-dependent diffraction efficiency by use of double volume gratings is presented, and experiments with LiNbO3:Fe crystal are also demonstrated. The experimental results indicate that this method can well suppress the polarization-dependent diffraction efficiency of a volume grating. Furthermore, the diffraction properties of the double volume gratings are almost independent of the polarization state of the readout beam. The relative values of the diffraction peaks are calculated on the basis of the relationship between index modulation and the state of polarization. The experimental values are in good agreement with the theoretical analyses.

Journal Article↗

PubMed1995

Dependence of male voiding efficiency on age, bladder contractility and urethral resistance: development of a voiding efficiency nomogram.

The influence of age, urethral resistance and bladder contractility on voiding efficiency was evaluated by pressure-flow studies in 138 men of a mean age of 60 years (range 18 to 86). From these studies the urethral resistance parameter was calculated and the maximum bladder contraction strength was determined. Premature fading of the bladder contraction was quantified by a bladder contraction strength decay factor. Voiding efficiency was expressed by the parameter of post-void residual urine volume as a percentage of the initial bladder volume. Multiple regression analysis showed that voiding efficiency depended significantly in descending order of importance on urethral resistance, maximum bladder contraction strength and bladder contraction strength decay factor. Patient age was not an independent factor. Maximum bladder contraction strength and bladder contraction strength decay factor were not correlated, suggesting that maximum bladder contraction strength and its decay constitute different properties of bladder contractile function. A voiding efficiency nomogram is proposed, making use of the values for maximum bladder contraction strength and urethral resistance in individual patients. Such a nomogram may have predictive value for the occurrence of acute retention but it must be tested prospectively.

Adolescent↗

PubMed2001

Administration and clearance of amphotericin B during high-efficiency or high-efficiency/high-flux dialysis.

Administration and clearance of amphotericin B infused during high-efficiency or high-efficiency/high-flux dialysis were studied in two end-stage renal disease patients requiring systemic antimycotic treatment for fungal peritonitis. Amphotericin B concentrations were measured in the arterial and venous dialysis ports as well as in the ultrafiltrate. Amphotericin B is poorly dialyzable while administered during hemodialysis sessions with high-efficiency (CA 210) or high-efficiency/high-flux (CT 190 G) membranes. Amphotericin B infusion during hemodialysis was well tolerated and can be administered conveniently in an outpatient dialysis setting, avoiding prolonged hospitalization for parenteral antifungal therapy.

Adult↗

PubMed1982

[Remarks on the value of psychological efficiency diagnostics for the diagnosis and therapy of alcoholism--response to Szewczyk on our "Chronic alcoholism and psychological efficiency"].

For a clarification of different viewpoints with respect to the importance of efficiency-diagnostic studies in chronic alcoholism, First the question is studied whether there is a common basis of judgement with Szewczyk. On the basis of examples it is shown that there is no agreement with regard to essential facts and contrary conclusions are drawn. The necessity of efficiency-psychological studies of the amnestic psychosyndrome as a constituting components of alcoholic changes of the personality is, for example, derived from diagnostic and therapeutical questions concerning the degree of severity and the pattern of the course of the disease. In progressing alcoholism, the constituting component "amnestic psychosyndrome" is frequently the dominating component in the sense of a pronounced organic psychosyndrome. After long-term abstinence, remarkable improvements of cognitive performances have been found with differentiating efficiency-diagnostic methods. From these facts alone the conclusion can be drawn that there is a wide range of indications for efficiency-diagnostic longitudinal and cross-sectional studies in chronic alcoholics.

Alcoholism↗

PubMed2005

Efficiency is a legitimate consideration in equitable distribution of cadaveric transplants: development of an efficiency-equality model of equity.

It is proposed that equity is a trade-off, or compromise, between equality and efficiency. The kidney transplant allocation algorithm currently used in the United Kingdom (NAT) was tested in the efficiency-equity model. In an exercise of 2000 past UK donors and a dynamic waiting list of 5000 potential recipients, 4000 transplants were allocated according either by NAT, by equal allocation (EQ) (a lottery), or by efficiency (EF). Diabetic recipients received 7.4% of transplants in NAT, 8.6% in EQ, and 0% in EF; paediatric recipients received 6.8% in NAT, 0.6% in EQ, and 0.7% in EF model. For HLA matching, there were 77.9% favourable or 000 matches in NAT, 3.0% in EQ, and 53.1% in EF. Predicted survival showed better outcomes in EF versus NAT (P < .0001) and in NAT versus EQ (P = .05). The NAT allocation system favours paediatric recipients and does not deny diabetics the chance of a transplant, broadly in line with published public and professional opinions. The NAT scheme achieves better HLA matching than the EF model, and this suggests that the rationale for allocation based primarily on HLA matching could be reexamined.

Algorithms↗

PubMed1996

The effect of wheelchair handrim tube diameter on propulsion efficiency and force application (tube diameter and efficiency in wheelchairs).

To determine the optimum tube diameter of a standard handrim-propelled wheelchair, the effect of tube size and shape on physiological and kinetic parameters was studied. Six able-bodied male subjects performed two tests on a wheelchair ergometer. Tests were performed against work loads comparable to every day use and with two different handrim tube diameters, a handrim with an oval 25 by 30 mm diameter (LR) and one with an 18 mm diameter (SR). The large tube diameter (LR) yielded slightly but significantly lower values for the physiological parameters. Gross mechanical efficiency was on average 7% for the LR and 6.3% for the SR. No significant results were found for force application parameters related to the direction of the applied force or the torque by the hand onto the handrim surface. As technique parameters could not explain the higher mechanical efficiency (ME) when using the LR, it is suggested that hand grip constraints in the push phase (finger flexor activity) might be responsible. Another possible explanation is that with a better hand grip using LR, less stabilization by the larger muscle groups at the elbow and shoulder is needed. The measured technique parameters seem to be determined by geometric constraints of the arm and shoulder. The technique requirements resulting from the forced trajectory of the propulsion movement are also likely to determine the technique parameters. Regarding the low mechanical efficiency of handrim propulsion, which is partly caused by the forced unfavorable trajectory of the hand, an alternative propulsion mechanism is suggested.

Adult↗