Correct

脚劲

/ jiǎo jìn / 
Strokes

Example

As a Noun

strength of one's legs

1
Mǔqīn
母亲
suīrán
虽然
shìlì
视力
bùxíng
不行
le
了
  
,
dàn
但
jiǎo
脚
jìn
劲
hái
还
bùcuò
不错
  
。

Mother has got strong legs although her eyesight is failing.