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Isometric arm strength and subjective rating of upper limb fatigue in two-handed carrying tasks.

Li KW, Chiu WS - PLoS ONE (2015)

Bottom Line: Two levels of load of carrying were tested for each of the male and female subjects.Exponential function based predictive equations for the isometric arm strength were established.The mean absolute deviations of these models in predicting the isometric arm strength were in the range of 3.24 to 17.34 N.

View Article: PubMed Central - PubMed

Affiliation: Department of Industrial Management, Chung Hua University, Hsin-Chu, Taiwan.

ABSTRACT
Sustained carrying could result in muscular fatigue of the upper limb. Ten male and ten female subjects were recruited for measurements of isometric arm strength before and during carrying a load for a period of 4 minutes. Two levels of load of carrying were tested for each of the male and female subjects. Exponential function based predictive equations for the isometric arm strength were established. The mean absolute deviations of these models in predicting the isometric arm strength were in the range of 3.24 to 17.34 N. Regression analyses between the subjective ratings of upper limb fatigue and force change index (FCI) for the carrying were also performed. The results indicated that the subjective rating of muscular fatigue may be estimated by multiplying the FCI with a constant. The FCI may, therefore, be adopted as an index to assess muscular fatigue for two-handed carrying tasks.

No MeSH data available.


Related in: MedlinePlus

Measuring the isometric arm strength.
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pone.0119550.g001: Measuring the isometric arm strength.

Mentions: The dependent variables of the experiment included isometric arm strength, FCI, and subjective rating of upper limb fatigue. When measuring the isometric arm strength, the subject stood straight on a steel plate. A chain, connecting to a loadcell, was anchored to the steel plate. The handle on the top of the chain was at the elbow height of the subject. The subject pulled the handle upward when his/her upper arm was straight down and by the sides (see Fig. 1). The subject pulled as hard as he/she could and continued for 4 to 6 seconds [23]. The maximum force during this period was recorded as F(t). This force is the maximum force output the subject could sustain under a normal two-handed carrying posture. Based on Equation (1) & (2), the modified FCI using the following equation was defined:FCI =/f(t2)−f(t1=0)f(t1=0)/=/MVCe−kLMVCt2−MVCe0)MVCe0/=/e−kLMVCt2−1/(5)where t2 is 0.5, 1, 1.5, .., or 4.


Isometric arm strength and subjective rating of upper limb fatigue in two-handed carrying tasks.

Li KW, Chiu WS - PLoS ONE (2015)

Measuring the isometric arm strength.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4368533&req=5

pone.0119550.g001: Measuring the isometric arm strength.
Mentions: The dependent variables of the experiment included isometric arm strength, FCI, and subjective rating of upper limb fatigue. When measuring the isometric arm strength, the subject stood straight on a steel plate. A chain, connecting to a loadcell, was anchored to the steel plate. The handle on the top of the chain was at the elbow height of the subject. The subject pulled the handle upward when his/her upper arm was straight down and by the sides (see Fig. 1). The subject pulled as hard as he/she could and continued for 4 to 6 seconds [23]. The maximum force during this period was recorded as F(t). This force is the maximum force output the subject could sustain under a normal two-handed carrying posture. Based on Equation (1) & (2), the modified FCI using the following equation was defined:FCI =/f(t2)−f(t1=0)f(t1=0)/=/MVCe−kLMVCt2−MVCe0)MVCe0/=/e−kLMVCt2−1/(5)where t2 is 0.5, 1, 1.5, .., or 4.

Bottom Line: Two levels of load of carrying were tested for each of the male and female subjects.Exponential function based predictive equations for the isometric arm strength were established.The mean absolute deviations of these models in predicting the isometric arm strength were in the range of 3.24 to 17.34 N.

View Article: PubMed Central - PubMed

Affiliation: Department of Industrial Management, Chung Hua University, Hsin-Chu, Taiwan.

ABSTRACT
Sustained carrying could result in muscular fatigue of the upper limb. Ten male and ten female subjects were recruited for measurements of isometric arm strength before and during carrying a load for a period of 4 minutes. Two levels of load of carrying were tested for each of the male and female subjects. Exponential function based predictive equations for the isometric arm strength were established. The mean absolute deviations of these models in predicting the isometric arm strength were in the range of 3.24 to 17.34 N. Regression analyses between the subjective ratings of upper limb fatigue and force change index (FCI) for the carrying were also performed. The results indicated that the subjective rating of muscular fatigue may be estimated by multiplying the FCI with a constant. The FCI may, therefore, be adopted as an index to assess muscular fatigue for two-handed carrying tasks.

No MeSH data available.


Related in: MedlinePlus