Typically, you need a fast lens coupled with a shutter speed of at least 250. This will require the ISO going up to at least 1600 (I don't know how high the D70 goes). The stadium lighting is also a factor.
For example, I know I need a faster lens...
Camera: Canon EOS 5D Mark II
Exposure: 0.004 sec (1/250)
Aperture: f/5.6
Focal Length: 300 mm
ISO Speed: 6400
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Lori Putman flickr
~No one can drive us crazy unless we give them the keys
~~Life isn't about waiting for the storm to pass, it's about learning to dance in the rain!
7D | 300L f/4 IS | 135L | 35L | 100/2.0 | 50/1.4
430 EX, 580 EX II Speedlites