I recently read Tom McCarthy's article on sprint training (That's an Excellent Question - How to Sprint.) and have a few concerns. First of all, I should point out that I agree with the technical things that Tom has recommended for improved sprinting. I also agree with the importance of practicing accelerations, starts and finishes at high speed in order to get good at them.
My understanding of sprint speed is that it involves a quick application of large forces from a balanced position. The balance on the ski is essential in order to be able to genereate the more powerful push and receive the resulting glide. It is also important to allow the relaxation phase that you suggest. I believe that we would agree about this understanding of sprinting. The question then becomes how best to develop the balance, quick application of large forces and ability to maintain it for 3 minutes and multiple rounds needed to sprint fast.
My first concern is with the amount of strength training that you propose. Weight training can help put on muscle mass and the forces one can generate but is generally done slowly and does not involve a quick application of force. It can be beneficial but is not the most important training element. Also, if the person is also interested in distance racing (as I understand Gavin to be) the increased bulk from lifting heavy weights can actually be detrimental. As a result, plyometrics are a lot more important for sprinting because they involve the quick application of maximal force and encourage the relaxation and power phases you encourage.
When I read your training suggestions, you are training less than 500 hours, which translates into 6 workouts a week in the dryland period. Yet you intend to lift weights twice and do plyometrics once per week. Thus, 3 weekly workouts are devoted to non-specific strength. The best way to develop balance on skiis is by skiing and rollerskiing. Furthermore, the best qay to train accelerations and speed for skiing is through short sprints and intervals on either skiis or rollerskiis. By spending 2-3 of your 6 workouts focused on general strength, where are these things going to be developed? The best training for ski racing is done on skiis and rollerskiis (technique is best learned here as is speed development). This season I have frequently trained with Erik Carleton, Ian Murray and Mike Argue (3 of Canada's top 10 sprinters and all raced the sprint at the Vernon World Cups). Erik has gone from a distance specialist to one who can sprint with the top Canadians this year despite never lifting a weight over 5kg (and then they were generally rocks being used in core strength exercises). He did this by improving his balance on skiis and increasing the speed of his intervals through the challenge from other sprinters. My next concern is with your suggestion of training less than 500 hours per year. I understand that you are currently very busy with a new job which has forced you to look at ways of maxmizing training time but that does not mean training less is ideal for sprinting. To be able to maintain high speeds for the last 30 seconds of world-class sprint courses or through multiple rounds requires a well developed aerobic base. The ability to flush lactates and function well aerobically to prevent their development is important for sprint racing. These abilities are developed through traditional distance and interval training. I cannot see these being developed well enough to be internationally competitive without training 600-700 hours/year as a senior racer. I understand that you have a large base from previous years which allows you to train less, but this is not a suggestion that works for those without.
Your suggestion that training less allows workouts to be better done is interesting. Doing all workouts effectively at a proper speed is essential for effective training. Being able to do workouts faster by being properly rested is highly beneficial. It comes from ensuring proper recovery between workouts and focus during workouts and from experience can be done with many more hours than you are proposing. I understand that many top international sprinters never train over 2 hours to ensure higher speed distance training and this may be a good idea. But they would compensate with more workouts to get in similar hours rather than fewer hours of training.
Finally, many skiers want not only to improve their sprinting, but also to continue to improve in distance races. Learning from your technical suggestions should help him in both kinds of races. However, for someone who still wants to be a fast distance skier, following your suggestions on hours and strength training would be detrimental. One can be among the top sprinters in Canada without compromising distance results by being able to effectively balance on a ski and doing effective high speed intervals. Doing more 10 second sprints on rollerskiis and skiis is probably the most effective way to improve sprinting and technique, while also helping for distance races.
Remember that the most effective training for ski racing (distance or sprint) is done on skiis and rollerskiis and that there is no substitute for focused hours and intervals in these activities.