1424090 jmdict A [id=1987290]
中堅[ichi1,news1,nf04]
ちゅうけん[ichi1,news1,nf04]
[1][n]
  nucleus; backbone; mainstay; key figure
[2][adj-no,n]
  medium-level; mid-level; middle-ranking; midsize
[3][n]
  main body (of troops); crack troops; select troops
[4][n][fld=baseb]
  center field; centre field; center fielder; centre fielder
[5][n]
  athlete competing in the middle-number match in a team competition, i.e. second in 3-on-3, third in 5-on-5 (kendo, judo, etc.)
  [see=1388610・先鋒・せんぽう[2]]