You are sprinting at full effort for 60 seconds, then your treadmill must drop speed instantly for a recovery jog. That is the reality of interval training. A machine that lags or feels unstable can ruin your workout and even cause injury. In this guide, we focus on two NordicTrack treadmills that are built for the demands of interval training. Whether you need a starter model for home or a premium setup with a large touchscreen, we have you covered. For more options, check out our top folding treadmills with incline.
Buying Guide
Speed and Incline Range
Interval training relies on quick changes between high and low intensity. A treadmill with a wide speed range gives you flexibility for sprints and recovery. The NordicTrack T Series 5 offers speeds up to 10 MPH and incline up to 10%, while the T Series 16 reaches 12 MPH and 12% incline. Both allow you to push hard and recover efficiently. For more details on incline features, read our budget incline treadmill guide.
Cushioning for Joint Protection
High impact from repeated sprints can stress your joints. Look for cushioning systems that absorb shock. The T Series 5 uses KeyFlex Cushioning to reduce joint impact. The T Series 16 goes a step further with SelectFlex Cushioning, which lets you adjust firmness from soft to firm. This is ideal if you want to customize your feel for different interval phases.
Smart Adjust and ActivePulse Technology
Automated adjustments can make interval training more effective. SmartAdjust learns your performance and changes speed and incline in real time. ActivePulse uses a heart rate monitor to keep you in your target zone. Both features require an iFIT membership but remove guesswork from your intervals. If you prefer manual control, you can always override settings.
Folding Design for Small Spaces
Not everyone has a dedicated gym room. A folding treadmill saves space when not in use. The T Series 16 features a foldable frame with assisted lowering. The T Series 5 is also compact. Both can be rolled away after your interval session. See our folding treadmills category for more space saving options.
Final Thoughts
For most people starting interval training at home, the NordicTrack T Series 5 Starter Treadmill for Real offers excellent value with its solid speed range and KeyFlex cushioning. If you want a more immersive experience with a larger screen and adjustable cushioning, the NordicTrack T Series 16 Treadmill is the better choice for serious interval athletes. Both machines deliver reliable performance for high intensity workouts.
Frequently Asked Questions
What speed do I need for interval training on a treadmill? Most interval programs require speeds between 6 and 12 MPH. A treadmill with a 0 to 10 MPH range, like the T Series 5, works for many users. The T Series 16 reaches 12 MPH for faster sprints.
Can I use a folding treadmill for HIIT? Yes, many modern folding treadmills are stable enough for high intensity intervals. Both NordicTrack models in this review fold for storage without sacrificing durability. For more options, see our best home treadmills for incline walking.
Do I need an iFIT membership for interval training? No, you can manually adjust speed and incline on both treadmills. However, iFIT membership unlocks SmartAdjust and ActivePulse, which automate interval changes based on your heart rate and performance.
What is the difference between KeyFlex and SelectFlex cushioning? KeyFlex offers a fixed level of impact absorption. SelectFlex lets you adjust firmness from soft to firm, giving you more control over joint support during different phases of your workout.
