Presentation on theme: "On the Cause of Experienced Care Workers’ Lower Back Pain: Considering Posture and the Strength of Back Muscle Ryuichi ITO Production."— Presentation transcript:
On the Cause of Experienced Care Workers’ Lower Back Pain: Considering Posture and the Strength of Back Muscle Ryuichi ITO Production Engineering of Advanced Engineering Course Niihama National College of Technology Japan-Taiwan symposium In 2012, In Taiwan
Background In Japan, 70 ％ of people in the care workers have complained of lower back pain. but People who are involved in care workers for many years is not that always cause lower back pain. Some care workers continue to work even if they have lower back pain. In other words: There are points unlikely to be lower back pain.
Experimental Method Examinee （ 18 pairs in total ） Care workers, and students of college of welfare make 9 pairs within each group. Patient （ 1 person ） We assumed patient who requires full support. Bathing care by two-persons She is female student who is weight about 48 kg. After the experiment, the patient evaluates the care level of comfort in five point scales.
Three-Dimensional Motion Analysis System Infrared camera Infrared marker Model of marker front back 20 points in total
Operation of Bathing Services There are four patterns. From wheelchair to edge of bathtub From edge of bathtub to bottom of bathtub from bottom of bathtub to edge of bathtub from edge of bathtub to wheelchair Task2Task1 Task3Task4
The Patient Evaluates the Care Level of Comfort in Five Point Scales 5 care workers Ｃ 4 care workers A care workers B care workers Ｅ 3 care workers Ｆ care workers Ｇ care workers Ｉ students ｇ 2 care workers Ｄ care workers Ｈ students a students h students i 1 students b students c students d students e students f 3 care workers Ｆ care workers Ｇ care workers Ｉ students g Excellent group Middle group Fair group
Definition of Waist Angle (θ) model of waist angle neck waist θ vertical direction
Moment Round the Waist of Care Worker L F ＬSＬS W P ・Ｌ S ・ Sin(θ) F ・Ｌ S ・ Sin(θ) W C ・Ｌ g ・ Sin （ θ’ ） θ‘ ＬgＬg WCWC WPWP （θ）（θ） θ
Strength of back muscle : F necessary in caring posture F ＞ W P +0.3 ・ W c total F ・Ｌ S ・ ＞ W P ・Ｌ S ・ + W C ・Ｌ g ・ H=height L S ＝ 0.28 ・ H L g ＝ 0.14 ・ H W C =0.6 ・ W c total F ＞ W P ・ + W C ・ L g / L S F ＞ W P ・ W c total ・（ 0.14H ） / （ 0.28H ） Sin （ θ ） L S / L S Moment of F ＞ Moment of W P ＋ Moment of W C
Assuming as follows; F ＞ W P ・ W C Care worker : weight is 60 (kg) Patient : weight is 50 (kg) F : Strength of back muscle F > ・ 60 = 68 (kg) If strength of back muscle of him is value less than 70 (kg), he has higher risk of lower back pain.
Definition of Roundness of the back (τ) back1 back2 waist τ Model of roundness of the back
Correlation Diagram of Strength of Back Muscle and Roundness of the Back Strength of Back Muscle [kgf]
Conclusion The risk of the lower back pain increases. 1. When expert care workers’ strength of back muscle is less than “Wp+0.3*Wc”, even if he has not had lower back pain. 2. When care workers have the posture of large roundness of the back.