This is work that is done at, or very near,
maximum speed. Although, this may seem obvious, it is sometimes not
realised that
only repetitions of up to a maximum of 5 or 6 seconds
can be completed at top speed. If it is longer than this, then this
is speed endurance - ie the maintenance of a high speed for the duration
of a run.
Many runners will find that they can complete
no more than 30-35m in this time, whilst even the very elite men
will cover at most 50-55m.
Often this kind of work will be done only in the summer and in
conjunction with the practice of starts (whether they be from
standing, crouching or blocks).
Also, it may be useful to do some
sprint work at the start of a session following it with some running
over longer distances to achieve two types of training in one
session. In these cases, the shorter, faster work should always be
done first or else the risk of injury is increased due to running at
top speed when fatigued.