How to Incorporate Longer Intervals for Endurance, Strength, and Mental Toughness (Part 1)

Short, high-intensity intervals are all the rage in fitness classes. They make for fun, engaging indoor cycling sessions that keep riders’ interest, and when done at the proper intensity, they can yield fantastic results and burn a ton of calories. Participants who love riding to the beat of the music are especially drawn to HIIT classes where instructors use the changing energy of verses and choruses to create built-in intervals. Surging hard on the chorus, easing up on the verse, gearing up on the bridge, and then repeating the surge—this pattern makes for exciting and dynamic rides.

I wholeheartedly believe that HIIT (high-intensity interval training) has an essential place in your program. These intervals, which can range from 10 seconds to 3 minutes, are effective and versatile. At ICA, we offer a wealth of resources to help you craft outstanding HIIT classes. Our profile archives are packed with options, including favorites like Turbo-Charged Intervals, Encore Intervals, The Ultimate HIIT, Lather, Rinse, Repeat (3-minute HIIT intervals), Lather, Rinse, Repeat Take 2 (4-minute intervals), Three-Peat Intervals (rock ‘n’ roll version), Three-Peat Intervals—Let’s Do This (an inspirational update to this fan favorite), You Can Do Anything for a Minute, Betwitched ,and so many more.

Over the years, we’ve even updated these popular profiles with new music, giving them fresh twists as theme rides or simply refreshing their energy for modern audiences. These resources are some of the most beloved by ICA members.

However, while HIIT is powerful, too much of it can backfire. Overusing short, high-intensity intervals can lead to overtraining and burnout, both for your riders and for yourself as an instructor. That’s where longer intervals come into play.

The Power of Longer Intervals

Longer intervals—lasting anywhere from 3 to 20 minutes—offer a different kind of challenge that’s equally (if not more) valuable for building endurance, strength, and mental toughness. These sustained efforts help riders develop their aerobic base, increase FTP (functional threshold power), and build stamina that serves them in both their cycling and daily lives.

Physiologically, longer intervals improve the body’s ability to clear lactate and work efficiently just below the lactate threshold, making them a cornerstone of any well-rounded fitness program. Mentally, they push riders to confront discomfort, develop focus, and build resilience—all essential traits for success on and off the bike.

[[However, if HIIT is all you ever do, you’re missing a crucial element of fitness: the power of longer, sustained intervals. These efforts—ranging from 6 to 20 minutes—unlock a higher level of endurance, strength, and mental focus, offering benefits that shorter intervals simply cannot match.]]

And yet, despite their importance, longer intervals are often met with resistance. Over the years, I’ve heard a range of objections from instructors at conferences and in online discussions:

• “They’re boring. My riders hate doing anything longer than 2 or 3 minutes.”
• “The music is boring. My class doesn’t like long songs.”
• “My riders only like HIIT; if they aren’t breathless, they don’t think they got a good workout.”
• “No one in my class is a cyclist, so there’s no reason to train like one.”

While these objections may reflect feedback from participants, much of the resistance to longer intervals often stems from projection. In many cases, it’s the instructor—not the riders—who avoids them. This reluctance can come from discomfort with the coaching skills needed to guide sustained efforts, reliance on external motivators like constant music changes or flashy drills, or simply not recognizing their own bias. It takes more effort, creativity, and understanding of exercise physiology to engage riders through longer intervals. Some instructors may not realize that their own hesitation—not the class’s—is what’s standing in the way.

Teaching longer intervals requires preparation, a deeper knowledge of exercise physiology, and a stronger focus on intrinsic motivation. It’s not as simple as shouting quick commands or relying on catchy tunes to guide the class. But the rewards—for both instructors and riders—are well worth the effort.

If all you ever do is HIIT, it’s like going to the gym and only working your arms. Strong arms are great, but they shouldn’t be your entire training plan and they certainly don’t contribute to a strong engine. Similarly, short, high-intensity efforts are just one piece of the fitness puzzle. Longer intervals in Zones 3 and 4 (tempo and threshold) build the aerobic foundation that supports everything else, including your riders’ ability to perform those intense bursts of effort they love so much.

In this four-part series, we’ll dive deep into why longer intervals matter, how to overcome the most common objections, and how to structure, coach, and deliver them in a way that keeps your riders engaged and motivated. Along the way, you’ll gain tools and strategies to elevate your coaching and inspire your riders to embrace the challenge—and the reward—of longer, sustained efforts.

Now that we’ve addressed common objections and why longer intervals are often avoided, let’s delve into the real value of teaching riders to embrace these challenging efforts. Here are six key reasons why incorporating longer intervals in Zones 3 and 4 can transform both their fitness and mindset:

[[Now that we’ve addressed common objections and why longer intervals are often avoided, let’s dive into the real value of teaching riders to embrace these challenging efforts. While low-intensity workouts (Zones 1 and 2) offer great wellness and cardiovascular benefits—particularly for beginners, those rehabbing an injury, or older adults—a 45- to 60-minute class is simply not long enough to produce the desired physiological adaptations of this intensity for the majority of indoor cycling participants. For general fitness and higher performance, it’s crucial to raise the intensity to Zones 3 and 4 during this time. Here are six key reasons why incorporating longer intervals in these zones can transform both your riders’ fitness and mindset:]]

Six Ways Longer Intervals Transform Your Riders’ Fitness and Mindset

Longer intervals in Zones 3 (“tempo,” RPE 4–6) and Zone 4 (“threshold,” RPE 7–8) may not leave riders breathless, but they are vital for building fitness and mental resilience. Here’s why incorporating them into your classes is transformative:

1. More Effective for Indoor Cycling Duration
   As stated above, Zone 2 steady-state work (RPE 2–3) is crucial for endurance athletes tackling hours-long rides outdoors. However, for indoor cycling participants riding 45–60 minutes a few times a week, its benefits are limited and often perceived as “boring.” In contrast, Zones 3 and 4 offer a satisfying challenge that’s both hard and rewarding. Crucially, these intensities only yield their full physiological benefits when sustained for extended intervals—short bursts simply don’t cut it.
2. Builds a Robust Aerobic Foundation for Everyone
   Even anaerobic athletes—like sprinters or those focused on high-intensity efforts lasting under 3 minutes—need a strong aerobic base. This foundation acts as the bedrock for all fitness, creating a “trickle-down” effect that enhances high-intensity efforts and overall performance. Without it, your riders are missing a critical piece of the fitness puzzle.
3. Optimizes Fat and Glucose Utilization
   Any effort lasting more than 3 minutes relies predominantly on the aerobic system. By training in these zones, you develop the lactate system, which optimizes the body’s ability to use fat and glucose as fuel. This not only delays fatigue but also boosts calorie burn and overall stamina. With benefits like these, it’s hard not to love sustained efforts.
4. Speeds Up Recovery
   A well-trained aerobic system leads to faster recovery between efforts. Whether it’s recovering mid-workout or bouncing back after a challenging ride, this ability is a game-changer for riders of all fitness levels.
5. Essential for Power-Based Training
   If you teach with power and aim to incorporate 20-minute FTP testing or other power-focused workouts, longer intervals are non-negotiable. Riders need to build both the physiological capacity to sustain higher efforts and the mental fortitude to stay committed. Mastering pacing during these intervals takes time, but introducing progressively longer efforts helps riders develop this critical skill.
6. Develops Mental Resilience for Life
   The accomplishment of sustaining longer intervals in an indoor cycling class isn’t just a physical achievement—it’s a powerful mental one. Enduring a 10- or 15-minute threshold effort helps riders build grit, focus, and confidence, not only on the bike but in other areas of life as well. You’ll often hear riders say they can still hear your voice in their heads when they push themselves in other activities that require endurance and commitment. This type of feedback is a testament to the lasting impact of your teaching and the mental resilience you’ve helped them cultivate. It’s a compliment that every instructor can appreciate—and a reminder of how deeply you can influence your riders’ overall mindset and confidence.

If you teach with power and plan on offering a 20-minute FTP test for your riders, it’s crucial to gradually prepare them for the mental and physical demands of this test. Longer intervals at sweet spot and threshold intensities are key to building the endurance needed to sustain higher efforts. Sweet spot, which is a blend of Zone 3 and Zone 4, is especially effective because it balances high intensity with the ability to make significant fitness gains while still allowing for a manageable recovery.

Even if FTP tests aren’t part of your class repertoire, I encourage you to incorporate longer intervals at these intensities. Many riders may even come to prefer them over the fast-paced, constantly changing efforts often found in HIIT-style classes. This was certainly the case for one of my riders, who shared his appreciation for the longer “blocks” of work. He said to me, “You know what I love about your classes? You give us blocks of work and you just let us do our thing. We have time to focus. Maybe I’m old-school, but I miss that—so few instructors do it anymore!” (He had moved to the US from the UK a few years before.)

Bill Pierce, a fellow ICA instructor and creator of numerous profiles, had a similar experience with his riders, who expressed how much they appreciated longer intervals. As he put it, his new riders were surprisingly drawn to these steady, focused efforts, which helped them build both physical and mental strength.

What’s Coming Next: Coaching Tips, Music Choices, and Preparing for FTP Tests

As we’ve explored, longer intervals are a powerful tool for improving endurance, strength, and mental toughness. But this is just the beginning. In part 2 of this series, I’ll dive into music choices that enhance mental focus and energy during these longer efforts. In part 3, I’ll offer nine tips to make longer intervals more engaging and exciting for your riders. And in part 4, I’ll share strategies to progressively prepare your riders for longer intervals, an essential part of building overall endurance and setting them up for success in FTP tests. Stay tuned! 

Long Tempo, Sweet-Spot, and Threshold Interval Profiles Available on ICA

At ICA, we have a wealth of profiles designed for tempo, sweet-spot, and threshold training. If you’re looking to get started with these types of intervals in your classes, these profiles are a great place to begin. And for ICA members, you’ll find a treasure trove of resources, including 50 templates for progressively longer interval profiles to help you tailor your own workouts. Here are just a few of the most popular options:

• The Sweetest Sweet Spot: Long intervals with a musical theme centered around “sweet” or “candy,” like “The Sweetest Taboo” by Sade.
• 3 x 15 Sweet-Spot Intervals: This profile keeps riders engaged by varying cadence and resistance.
• That Sweet Spot: A structured variation on sweet-spot intervals with consistent changes in cadence and resistance.
• Sweet-Spot Threshold Ladder: A flexible profile that can be adjusted to meet the needs of any fitness level.
• Negative Split Threshold Intervals: A pacing strategy that helps riders perform the second half of the interval at a higher intensity.
• Negative Split Intervals. Set a baseline effort for the first song then beat it in the second song.
• Over/Under Intervals: Hard, long intervals that push your riders’ limits and build stamina quickly.
• Ebb and Flow: A unique profile using alternating slower and faster cadences to simulate one continuous interval.
• Reverie, Aerobic Intervals: A tempo profile with 12-minute intervals designed to ease your riders into mental focus.
• The Delicious Ride: One of ICA’s foundational rides, perfect for mastering tempo and longer-duration efforts.

These profiles, plus many more, are available for ICA members. If you’re not yet a member, now is the perfect time to join and get access to all these invaluable resources!

Curious about exploring more profile options at ICA? Dive into our 20-week suggested class schedule, featuring 40 unique profiles complete with exciting playlists and empowering coaching cues. These tools are designed to keep your classes fresh, engaging, and effective—so you’ll never run out of inspiration for what to teach next!