Journal List > Korean J Sports Med > v.34(1) > 1054577

Kim, Han, and Zhang: Norm-Referenced Criteria for Isokinetic Strength of the Lower Limbs for the Korean High School Baseball Players

Abstract

This study concerns norm-referenced criteria for isokinetic strength of the lower limbs for the Korean high school baseball players. Two hundred one high school baseball players were participated in this study. They didn't have any medical problem at the lower limbs. Each test was conducted four times in the ankle plantar flexion/dorsiflexion test at 30o/sec speed, knee flexion/ extension test was conducted four times at 60o/sec speed. Humac Norm (CSMI, USA) system was used to obtained the value of peak torque, peak torque % body weight. The results were presented as a norm-referenced criterion value using 5-point scale of cajori, by 5 group (6.06%, 24.17%, 38.30%, 24.17%, and 6.06%) and a few suggestions from this study as follows. The provided criterion of peak torque and peak torque % body weight are very useful information for baseball palyers, baseball coach, athletic trainers and sports injury rehabilitation experts, to utilize as an objective clinical assessment data.

REFERENCES

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Fig. 1.
Knee extension/flexion range of motion & seated position.
kjsm-34-48f1.tif
Fig. 2.
Ankle plantar flexion/ dorsiflexion range of motion & prone position.
kjsm-34-48f2.tif
Fig. 3.
The comparison of peak torque dorsiflexor and plantar flexor of ankle joint in each sports. (A) The values of peak torque dorsiflexor and plantar flexor of the right side ankle joint. (B) The values of peak torque dorsiflexor and plantar flexor of the left side ankle joint.
kjsm-34-48f3.tif
Fig. 4.
The comparison of peak torque % body weight (PT%BW) dorsiflexor and plantar flexor of ankle joint in each sports. (A) The values of PT%BW (%) dorsiflexor and plantar flexor of the right side ankle joint. (B) The values of PT%BW (%) dorsiflexor and plantar flexor of the left side ankle joint.
kjsm-34-48f4.tif
Fig. 5.
The comparison of peak torque extensor and flexor of knee joint in each sports. (A) The values of peak torque extensor of the right side knee joint. (B) The values of peak torque extensor of the left side knee joint. (C) The values peak torque flexor of the right side knee joint. (D) The values peak torque flexor of the left side knee joint.
kjsm-34-48f5.tif
Fig. 6.
The comparison of peak torque % body weight (PT%BW) extensor and flexor of knee joint in each sports. (A) The values of PT%BW (%) extensor of the right side knee joint. (B) The values of PT%BW (%) extensor of the left side knee joint. (C) The values PT%BW (%) flexor of the right side knee joint. (D) The values peak torque % body weight flexor of the left side knee joint.
kjsm-34-48f6.tif
Table 1.
Characteristics of subjects
Number Height (cm) Weight (kg) Age (yr) Career (yr) Body mass index (kg/m2) %Body fat (%)
201 176.20±5.61 76.58.±10.98 17.66±0.70 6.68±1.57 36.34±4.99 15.92±5.6

Values are presented as mean±standrad deviation.

Table 3.
The values of peak torque & peak torque % body weight ankle dorsiflexor and plantar flexor at 30o/sec speed
Muscle group Peak torque (Nm) Peak torque % body weight (%)
Dorsiflexor    
Right 34.06±5.81 45.19±6.97
Left 33.41±6.08 44.18±7.28
Plantar flexor    
Right 79.22±22.20 103.04±27.53
Left 77.17±20.45 101.81±26.14

Values are presented as mean±standrad deviation.

Table 2.
Norm-referenced criterion value using 5-point scale of cajori
Scale 5 4 3 2 1
Percentage (%) 6.06 24.17 38.30 24.17 6.06
Stage Very low Low Moderate High Very high
Table 4.
Norm-referenced criterion values of PT & peak PT%BW ankle dorsiflexor and plantar flexor at 30o/sec speed
Variable Stage Very low Low Moderate High Very high
PT (Nm) Dorsiflexor          
Right <25.4 25.4−31.2 31.3−36.9 37.0−42.7 ≥42.8
Left <24.4 24.4−30.3 30.4−36.4 36.5−42.5 ≥42.6
Plantar flexor          
Right <46.0 46.0−66.1 66.2−90.3 90.4−112.5 ≥112.6
Left <46.6 46.6−66.8 66.9−87.3 87.4−107.7 ≥107.8
PT%BW (%) Dorsiflexor          
Right <34.8 34.8−41.6 41.7−48.6 48.7−55.5 ≥55.6
Left <33.4 33.4−40.4 40.5−47.7 47.8−55.0 ≥55.1
Plantar flexor          
Right <61.8 61.8−89.1 89.2−116.7 116.8−144.2 ≥144.3
Left <62.7 62.7−88.6 88.7−114.8 114.9−140.9 ≥141.0

PT: peak torque, PT%BW: peak torque % body weight.

Table 5.
The values of peak torque & peak torque % body weight knee flexor and extensor at 60o/sec speed
Muscle group Peak torque (nm) Peak torque % body weight (%)
Flexor    
Righ 97.12±23.08 127.08±26.44
Left 96.18±23.92 127.09±30.69
Extensor    
Righ 198.17±36.83 258.95±44.55
Left 195.93±41.71 256.96±49.21

Values are presented as mean±standrad deviation.

Table 6.
Norm-referenced criterion values of PT and PT%BW knee flexor and extensor at 60o/sec speed
Variable Stage Very low Low Moderate High Very high
PT (Nm) Extensor          
Right <143.1 143.1−179.7 179.8−216.5 216.6−253.3 ≥253.4
Left <133.4 133.4−174.9 175.0−216.7 216.8−258.4 ≥258.5
Flexor          
Right <62.6 62.6−85.5 85.6−108.5 108.6−131.6 ≥131.7
Left <60.4 60.4−84.1 84.2−108.1 108.2−132.0 ≥132.1
PT%BW (%) Extensor          
Right <192.3 192.3−236.6 236.7−281.2 281.3−325.7 ≥325.8
Left <183.3 183.3−232.3 232.4−281.5 281.6−330.7 ≥330.8
Flexor          
Right <87.5 87.5−113.8 113.9−140.2 140.3−166.7 ≥166.8
Left <81.2 81.2−111.7 111.8−142.3 142.4−173.0 ≥173.1

PT: peak torque, PT%BW: peak torque % body weight.

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