1Professor, College of Nursing, Pusan National University, Busan, Korea
2Full-time Lecturer, Department of Nursing, Silla University, Busan, Korea
1Professor, College of Nursing, Pusan National University, Busan, Korea
2Full-time Lecturer, Department of Nursing, Silla University, Busan, Korea
Copyright © 2008 Korean Society of Nursing Science
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| Predictors | F | β | R2 | Additional R2 | Mediating effect | 
|---|---|---|---|---|---|
| Muscle strength of lower extremity (MSLE) | |||||
| Equation 1. MSLE → depression | 16.877*** | -.254*** | .064 | - | |
| Equation 2. MSLE → falls | 4.914* | -.140* | .020 | - | |
| Equation 3. Depression → falls | 9.941*** | .244*** | .075 | - | |
| MSLE → falls | -.078 | .006 | Yes | ||
| Muscle strength of left upper extremity (MSLUE) | |||||
| Equation 1. MSLUE → depression | 24.161*** | -.300*** | .090 | - | |
| Equation 2. MSLUE → falls | 7.294** | -.170** | .029 | - | |
| Equation 3. Depression → falls | 10.422*** | .234*** | .079 | - | |
| MSLUE → falls | -.100 | .009 | Yes | ||
| Muscle strength of right upper extremity (MSRUE) | |||||
| Equation 1. MSRUE → depression | 23.800*** | -.298*** | .089 | - | |
| Equation 2. MSRUE → falls | 7.966** | -.177** | .031 | - | |
| Equation 3. Depression → falls | 10.659*** | .232*** | .080 | - | |
| MSRUE → falls | -.109 | .011 | Yes | 
 
									General Characteristics of Participants (N=247)
| Characteristics | n | % | 
|---|---|---|
| Gender | ||
| Male | 38 | 15.4 | 
| Female | 209 | 84.6 | 
| Age (yr) | ||
| 65-69 | 16 | 6.5 | 
| 70-79 | 138 | 55.8 | 
| 80 or more | 93 | 37.7 | 
| Mean±SD | 77.9±5.4 | |
| Education | ||
| None | 133 | 53.9 | 
| Elementary school | 65 | 26.3 | 
| Middle school or higher | 49 | 19.8 | 
| Spouse | ||
| Yes | 58 | 23.5 | 
| No | 189 | 76.5 | 
| Living arrangement | ||
| Children offspring | 117 | 47.4 | 
| Spouse | 43 | 17.4 | 
| Solitude | 86 | 34.8 | 
| Others | 1 | 0.4 | 
| Perceived economic status | ||
| High | 6 | 2.4 | 
| Middle | 120 | 48.6 | 
| Low | 121 | 49.0 | 
| Perceived health status | ||
| Good | 47 | 19.0 | 
| Moderate | 81 | 32.8 | 
| Poor | 119 | 48.2 | 
| Regular exercise | ||
| Yes | 119 | 48.2 | 
| No | 128 | 51.8 | 
| Pre-existing chronic disease | ||
| Yes | 168 | 68.0 | 
| No | 79 | 32.0 | 
Descriptive Statistics of Research Variables (N=247
| Variables | Mean | SD | Actual range | Reference range | 
|---|---|---|---|---|
| M. strength of lower ext. (Frequency) | 12.67 | 4.46 | 0-28 | |
| Male | 14.45 | 4.22 | 4-26 | 8-18 | 
| Female | 12.35 | 4.43 | 0-28 | 8-16 | 
| M. strength of upper ext. (Hand grip) | ||||
| Left hand (kg) | 14.89 | 5.66 | 0-35 | |
| Male | 21.91 | 6.58 | 0-35 | 30-40 | 
| Female | 13.61 | 4.42 | 0-24 | 17-24 | 
| Right hand (kg) | 15.20 | 5.50 | 0-36 | |
| Male | 21.94 | 6.21 | 0-36 | 30-40 | 
| Female | 13.98 | 4.36 | 0-33 | 17-24 | 
| Depression | 7.30 | 3.82 | 0-15 | 0-5 | 
| Falls | ||||
| Frequency | 0.68 | 1.13 | 0-4 | |
| n | % | |||
| Yes | 84 | 34.01 | ||
| 1 | 38 | 45.24 | ||
| 2 | 20 | 23.81 | ||
| 3 | 15 | 17.86 | ||
| 4 or more | 11 | 13.10 | ||
| No | 163 | 65.99 | 
M.=Muscle; Ext.=Extremities.
Correlations among Study Variables (N=247)
| M. strength. of lower ext. r (p) | M. strength of left upper ext. r (p) | M. strength of right upper ext. r (p) | Depression r (p) | Falls r (p) | |
|---|---|---|---|---|---|
| M. strength of lower ext. | |||||
| M. strength of left upper ext. | .412 (<.001) | ||||
| M. strength of right upper ext. | .444 (<.001) | .781 (<.001) | |||
| Depression | -.254 (<.001) | -.300 (<.001) | -.298 (<.001) | ||
| Falls | -.140 (.028) | -.170 (.007) | -.177 (.005) | .264 (<.001) | 
M.=Muscle; Ext.=Extremities.
Mediating Effects of Depression in the Relationship between Muscle Strength of Extremities and Falls (N=247)
| Predictors | F | β | R2 | Additional R2 | Mediating effect | 
|---|---|---|---|---|---|
| Muscle strength of lower extremity (MSLE) | |||||
| Equation 1. MSLE → depression | 16.877 | -.254 | .064 | - | |
| Equation 2. MSLE → falls | 4.914 | -.140 | .020 | - | |
| Equation 3. Depression → falls | 9.941 | .244 | .075 | - | |
| MSLE → falls | -.078 | .006 | Yes | ||
| Muscle strength of left upper extremity (MSLUE) | |||||
| Equation 1. MSLUE → depression | 24.161 | -.300 | .090 | - | |
| Equation 2. MSLUE → falls | 7.294 | -.170 | .029 | - | |
| Equation 3. Depression → falls | 10.422 | .234 | .079 | - | |
| MSLUE → falls | -.100 | .009 | Yes | ||
| Muscle strength of right upper extremity (MSRUE) | |||||
| Equation 1. MSRUE → depression | 23.800 | -.298 | .089 | - | |
| Equation 2. MSRUE → falls | 7.966 | -.177 | .031 | - | |
| Equation 3. Depression → falls | 10.659 | .232 | .080 | - | |
| MSRUE → falls | -.109 | .011 | Yes | 
*p<.05
**p<.01
***p<.001.
Equation 1. IV → mediator to check beta and R2; Equation 2. IV → DV to check beta and R2 (it should be significant to test mediator effect); Equation 3. Step 1: mediator → DV to check beta and R2; Step 2: IV → DV to check beta and R2.
						 M.=Muscle; Ext.=Extremities.
						 M.=Muscle; Ext.=Extremities.
						 p<.05 p<.01 p<.001. Equation 1. IV → mediator to check beta and R2; Equation 2. IV → DV to check beta and R2 (it should be significant to test mediator effect); Equation 3. Step 1: mediator → DV to check beta and R2; Step 2: IV → DV to check beta and R2.
