Most skiers who spend weeks training for endurance are actually training glycolytic capacity. They run intervals until they burn. They do metabolic conditioning circuits. They chase the lactate and call it preparation for the mountain. Then they ski three hard days and wonder why they’re cooked on day four.

This is the wrong training pathway for how your body actually skis.

The Energy System Reality

Skiing draws power from three energy systems. Understanding which one matters — and which one doesn’t — changes everything about how you train.

The alactic system handles short, maximal efforts: a hard set of turns, a mogul absorption, the explosive drive out of a transition. It lasts roughly 10 seconds before depletion.

The aerobic system sustains longer efforts at moderate intensity: cruising groomers, linking turns down a wide pitch, recovering between runs. It is highly efficient and produces minimal fatigue byproduct.

The glycolytic system bridges the gap. It activates during efforts between 30 seconds and a few minutes of sustained high intensity. It produces power, but it also produces lactate and hydrogen ions that slow muscle contraction and accumulate in the bloodstream and muscle tissue.

Here is the problem: skiing does not primarily demand glycolytic work. A single run might last 15 minutes, but it is not 15 minutes of continuous intensity. It is a series of turns, each lasting 2-5 seconds of hard effort, separated by recovery moments between turns. Over a full ski day — particularly a multi-day trip — you need the alactic system to produce power on demand and the aerobic system to recover between efforts.

Training the glycolytic system trains capacity you do not need and produces fatigue you cannot recover from quickly.

Why Glycolytic Training Fails for Multi-Day Skiing

Recovery capacity decreases with age. This is not conjecture; it is measurable. Masters skiers recover more slowly from high-lactate efforts, and the fatigue from glycolytic training persists into the next day. Train hard glycolytically on Monday, and your power output on Tuesday suffers.

Now extend this across a ski week. Day one is strong. Day two is fine. Day three, the glycolytic load accumulates. By day four or five, you are not skiing poorly because you are out of shape. You are skiing poorly because your body has not recovered from the accumulated metabolic byproduct of training.

The HIIT-trained skier feels strong on day one and two. The AGT-trained skier skis well on day one through day five — and beyond.

What Anti-Glycolytic Training Actually Is

Anti-glycolytic training (AGT) is a conditioning approach that keeps work in the alactic and aerobic energy systems. It is not low-intensity. It is not easy. It is specific.

In an AGT session, you perform work intervals at high intensity — RPE 6-7, smooth, powerful, sustainable — followed by full recovery. The recovery is the key. Unlike traditional intervals where you rest 30-45 seconds and return to work while still fatigued, AGT uses longer rest periods so that you complete each work interval feeling fresh and powerful.

The intensity is high. The recovery is complete. The result is adaptation in the alactic and aerobic systems without glycolytic accumulation.

An AGT Session in Practice

Here is what an actual AGT session looks like. This example uses kettlebell swings, a tool that develops hip extension power while fitting neatly into the alactic/aerobic window.

Kettlebell Swing AGT Session (20 minutes total)

• Warm-up: 5 minutes (light movement, mobility prep, no lactate accumulation)
• Work intervals: 15 kettlebell swings, performed with explosive hip extension and controlled descent. Each set takes roughly 30-40 seconds.
• Rest: 90-120 seconds complete recovery between sets.
• Sets: 6-8 rounds
• Target: Power output remains consistent across all sets.
• Heart rate guidance: Work intervals should reach 75-85% of max heart rate. Rest periods should drop to 60-65% of max.
• Intensity check: Nasal breathing during work intervals should be possible but challenging.

The entire session is 20 minutes. The next day, your power is undiminished.

Other effective AGT tools: sled push (30-40 yards, walk back to recovery), assault bike intervals (20-30 seconds of hard effort, 2 minutes of easy spinning), rowing machine intervals (500 meters with full recovery between sets).

The common thread: high intensity, complete recovery, consistency of power output across all sets.

The Ski-Day Translation

Here is where AGT proves itself: on the mountain.

A skier who has trained glycolytically feels strong on opening day. They have trained work capacity. But by mid-week, that accumulated lactate debt compounds. Their legs feel heavy. Their turn initiation slows.

A skier who has trained with AGT skis hard on day one and day five with the same edge sharpness and power. The alactic and aerobic adaptations transfer directly. Recovery between runs is complete.

The CMH heli-skiing trips — 144,000 vertical feet in a week — are the upper end of this: a 64-year-old can absorb 50-60 runs across challenging terrain in a week because the training system built for that has prioritized recovery capacity and sustainable power, not glycolytic threshold.

The Role of HIIT — And Why AGT Comes First

HIIT has legitimate uses. Glycolytic capacity matters for certain sports. It produces rapid fitness gains in younger athletes with higher recovery capacity.

But for masters skiers, especially those who ski multi-day trips, AGT produces better outcomes. Build your conditioning base — especially in the off-season — with AGT.

What You Need to Know Before Starting

AGT requires discipline in a different way than traditional conditioning. The challenge is not the intensity of effort. It is the restraint to rest fully and stop when power output drops.

Track your power output across sessions. Over 6-8 weeks, you will notice that ski days feel less demanding and that a full week of skiing no longer requires an extra recovery day.

Chapters 18 and 19 of Ski Strong for Life cover the full AGT methodology. The Fall Transition program integrates AGT conditioning into weeks 5-12.

The Takeaway

Endurance for skiing is not built by training until you burn. It is built by staying aerobic and alactic, recovering completely, and repeating that contrast over weeks.

Train the energy systems you actually use. The difference is felt on the mountain.