Skiing economy is influenced by many internal and external characteristics.

The internal characteristics include:

• Biomechanics.

Skiing mechanics influence economy because any unnecessary movements (and therefore unnecessary muscle contractions) increase the amount of oxygen the body consumes to maintain the pace. The more optimal the mechanics including proper body posture, weight shift and rhythmical timing with coordination, and so on-the more economical and efficient the skier will be.

• Muscle fiber recruitment.

The less muscle that’s recruited to ski at the desired pace, the better. Any extra muscle activity reduces economy because more muscle activity means more oxygen is being used. Number of slow-twitch muscle fibers. Slow-twitch fibers are made for aerobic activities like cross country skiing. They’re much more efficient than fast-twitch muscle fibers, which are made for sprinting.

• Number of mitochondria.

More mitochondria mean more aerobic factories to spread around the work, which improves economy.

• Body weight.

The less someone weighs, especially from the waist down and even more so from the knee down, the less work the body does to transport the person’s weight when he runs. Slim legs are more economical because they require less energy to lift off the ground. Adding weight, particularly at the end of a long lever, requires more energy to move the lever and makes the work harder.

• Ability of tendons to store and use elastic energy.

Like a rubber band when stretched, the Achilles tendon, which connects the calf muscle to the heel bone, stores energy when the foot lands on the ground and gives back that energy at push-off, helping to propel us forward. Long, thin Achilles tendons are good at storing energy with each step. They make the legs work like springs, which is very economical.

The external characteristics include:

• Training.

Training is the biggest external factor that affects skiing economy. Increasing weekly mileage, adding faster-paced running or skiing to a base of mileage, and strength training all improve running economy.

• Lightweight and high-performance gears.

Lightweight high-performance gears that still provide better gliding improve skiing economy and prevent fatigue from long endurance race or training.

• Wind.

Skiing into the wind decreases economy because there is more air resistance to overcome.

• Snow condition and temperature.

Snow conditions significantly impact cross-country skiing, affecting both glide and grip. Warm, wet snow can be slow and sticky, requiring different waxing techniques than cold, dry snow, which can offer better glide. Factors like temperature, snow type (powdery, wet, icy), and track conditions all play a role in how skis perform. 

• Gears.

Cross-country ski boots and skis, while seemingly simple, play a crucial role in performance. Boots, designed for either classic or skate skiing, dictate the level of support, flexibility, and control. Skis, chosen based on technique and terrain, affect glide and maneuverability. The right combination of boots and skis is essential for comfort, efficient technique, and overall enjoyment on the slopes.