Overspeed HIIT in Lower-Body Positive Pressure Treadmill Improves Running Performance

Area of Science:

• Exercise Physiology
• Sports Science
• Running Performance

Background:

• Optimal high-intensity interval training (HIIT) protocols for enhancing running performance, including running economy (RE), anaerobic threshold (AT), and maximal oxygen uptake (VO2max), remain under investigation.
• Lower-body positive pressure (LBPP) treadmills allow for partial unloading of runners, enabling training at supramaximal speeds and potentially offering a novel approach to HIIT.

Purpose of the Study:

• To investigate the efficacy of an overspeed HIIT protocol utilizing LBPP technology in trained runners.
• To compare the effects of LBPP-assisted HIIT versus conventional treadmill HIIT on key running performance indicators.

Main Methods:

• Eleven trained runners were randomized into either an LBPP group (n=6) or a control (CON) group (n=5).
• Both groups underwent an 8-session, 4-week HIIT program involving intervals at 100% of velocity at VO2max (vVO2max) with a 1:1 work-to-recovery ratio.
• The LBPP group trained at 90% of their body weight, while the CON group used a regular treadmill. Performance outcomes included 2-mile time trial, VO2max, vVO2max, AT, time to exhaustion (Tlim), and RE.

Main Results:

• Significant improvements in vVO2max and Tlim were observed in the LBPP group compared to CON.
• Both groups showed improvements in field performance (2-mile time trial) and VO2max, with no significant difference between groups.
• Submaximal heart rate decreased in both groups, indicating improved cardiovascular efficiency. Running economy (RE) remained unchanged.

Conclusions:

• A 4-week HIIT protocol at 100% vVO2max effectively enhances running performance, vVO2max, and submaximal heart rate in trained runners.
• The performance improvements achieved with LBPP-assisted HIIT are comparable to those from standard treadmill HIIT.
• LBPP treadmills offer a viable alternative for implementing demanding HIIT sessions, potentially allowing for training at higher speeds or reduced impact.