I love sprinting to increase overall athletic capacity and as a way of stimulating the metabolism and mental strength. It is a great base and peaking mechanism for strength and power athletes who generally neglect cardio specific strength training.
Here's my sprint workout that I've developed for rock climbing.

1/2 mile warm up at 50-60% (aerobic)
Active stretching: kicks, leg swings for increasing range of motion.

hi-intensity/technical warm-ups:
(3) 100m emphasizing technique, breathing and tempo:

60 meter increasing stride length and speed to 70%, slowly deccelerating last 40m RI=1'
80 meter increasing stride length and speed to 80%, slowly deccelerating last 20m RI=2'
100 meter continuous steady build to 90% RI=3'

Anaerobic Target:
200m building to 90%
RI=3'
400m@80%
RI=3'
400m@ 90%
RI=3'
400m@ 80%
RI=3'
400m@ 70%
RI=3'
100m @ 95%
RI=3'
100m @ 90%

Immediate 400m cool down

I build the number of target anaerobic range sprints so the structure of the workout evolves as follows:

Week 1: (3) 100m warm-up builds, (1)x 200m, (3)x400m, (1)x 200m, (1)x100m Week 2: (3) 100m warm-up builds(1)x 200m, (4)x400m, (2)x 100m Week 3: (3) 100m warm-up builds, (6)x400m, (2)x 100m

Week 4: (3) 100m warm-up builds, followed by a 5' repeat cycle including multiple sprints of different distances and rest where the athlete must budget their allotted time to complete the tasks.

Example:
5' set #1-3: 200m/R=approx 2:30/100m/R=approx 1:30
set #4-5: 100m/R=1:20'/100m/R=1:20/100m/R=1:30

Notes:
This is based on a cross-training running program of one sprint session/week and 2 other aerobic 20-25' runs/week to offer enough support volume and anatomical stress adaptation to impact for such strength based sprinting workouts. A total of 8-10 sprints/session is ideal for the power athlete - a short concise workout session. I try to keep my sprint sessions to 25-30'
- not including aerobic warm-up/cool down.

While it would appear that 400m is too great a distance for a "power" athlete, the type of 400m that I run is very specific to explosive sports that also require maintaining anaerobic threshold. I generally "explode" the first 40-50m (to build start speed) followed by 250-300m of "striding and riding", finishing with an acceleration "boost" for the last 50-100m (depending on fatigue, perceived output, fitness level and which interval it is within the workout). 300m can be substituted for 400m distance to build up to 400m distance or to adjust the level of output to accommodate the athletes level of fatigue.

In regard to workout #4: These sprints are fast with the 200m being used alternately in the same 5' set with the 100m to vary the type of speed output and resistance vs fatigue levels and time management (important for mental adaptation under stress). The 200m is run like the 400's - 50 fast, 100 "striding and riding", and an acceleration of the final 50m. The 100m is run as a constant acceleration build for the full duration and finally degenerates to a maintained pace due to the limitations of the athlete's anaerobic threshold and recovery abilities. The emphasis of this workout is on speed vs recovery.

Week #5 I would return to the Week #1 sprint workout schedule and vary the speed and intensity of the sprints to modify the workout to accommodate a higher level of fitness rather than increasing the volume or diminishing the rest interval too much. This helps avoid over training and facilitates optimal recovery and maximum recruitment for each bout. A running specific athlete would want to gradually diminish the RI and build significant volume. However, I believe that the non-running strength based athlete (such as rock climbers) should emphasize intensity over mileage. After all, it is only supplemental cross-training!

I have noticed that in addition to a stronger cardio vascular system, this type of training tends to build strong mental coping abilities important for adapting in competition, bone density, breath control, an aggressive/dynamic/explosive disposistion, more testosterone and makes you absolutely ripped. Struggling on a hard climb seems relatively easy after I've been doing this type of sprint training.

Timy Fairfield is a world-champion rock climber in bouldering. He also trains athletes in a variety of sports. You can see his website at www.timyfairfield.com.