Here are some general ideas for you to use on client since I don’t know him:
-Lots of leg work (lunges and squats in all 3 plains of motion, hops/jumps in all 3 plains of motion), stairs and sliding mountain climbers
-Core work (planks, flutter kicks, bicycles, etc.)
-Hills runs and some sprints, bike intervals for muscular endurance
-Rotations using cables, Keizer machines, ViPRS
-Rope work for upper body endurance
Assuming he has no medical issues or other limitations, the above list of recommendations should be able to help him get ready for his skiing trips. You will have to decide on the final selection of exercises, duration and frequency since it has to be customized according to his abilities and fitness level.
I hope this helps.
Ive had great success with a series of BOSU exercise:
1. Step back in a lunge position with front leg on the BOSU.
Back foot moves from 6 O’clock to 4 O’clock to 8 O’clock without coming out of the lunge.
slowly progress repetitions
2. BOSU Squat n Rock – stand on BOSU flat side up. Hold squat position while rocking side to side.
3. UP UP Down Down on BOSU – From standing position on the BOSU, drop one knee down to the BOSU. Repeat the knee. Then back to standing one leg at a time.
Altitude is a little tricky. Other than making him breathe through a coffee straw (I do not recommend ), You could progress his cardiovascular workout to include sprint intervals or tabatas (20sec. fast/10sec. recovery)
After he is fatigued you could have him stand on one leg and pick up his water bottle from different clock positions. i.e. he is standing in the middle of a clock. He would place the water bottle anywhere from 3 O’clock to 9 O’ clock and everywhere in between. Simply repeatingly picking up and putting down the water bottle while balancing on the one leg.
This will require balance and finer motor skills while fatigued yet still a relatively safe exercise.
All fun stuff. Hope this helps
Good answers. Obviously working on quad and calf strength is essential. Half-squats, plantar flexion (weight machine or elastic bands,) and full squats if the snow is going to be deep! The only way, that I’m aware of, to train for altitude is to progressively work out at altitude for 10-14 days. You didn’t mention the altitude your client is going to be skiing in. Above 14,000′ definitely requires acclimatization. I like the water bottle-clock position routine suggested by Timothy. It’d be great for assessing balance skills. I hope your client has a great ski trip!
The effects of training and playing at altitude are almost impossible to replicate in the gym. Some people are using oxygen restriction masks to simulate altitude. But since the mask is only worn for a short period, the effects on the blood cell count are non existent. The best advice I would give you is to teach your client about acclimation once they get to the site. You should search “acclimating to elevation for exercise” and/or similar searches to get the information. This is a progression of time and intensity over the duration of the trip. As I don’t know the elevation, length of the trip, current elevation of the client’s location, etc.; it would not be a simple matter for me to lay out all the options.