# Tolerability of high intensity interval training (HIIT) in individuals living with knee OA and at risk for cardiovascular disease: A prospective cohort study (THIPO)

## TL;DR

A 12-week high intensity interval training program was found to be tolerable for people with knee osteoarthritis and cardiovascular disease risk.

## Contribution

This study demonstrates the feasibility of HIIT in a population with knee OA and elevated CVD risk.

## Key findings

- Average attendance to the HIIT sessions was 88%.
- 46% of participants experienced a reduction in knee pain over the 12 weeks.
- The program was tolerable for individuals with mild-to-moderate difficulties in pain and function.

## Abstract

To explore the tolerability of a 12-week High Intensity Interval Training (HIIT) program in individuals with knee osteoarthritis (OA) at elevated risk for cardiovascular disease (CVD).

Forty-one individuals with knee OA and elevated CVD risk participated in a 12-week HIIT program with three weekly supervised sessions (36 in total) on treadmills, cross-trainers, row- and cycle ergometers. The program comprised a 10-min warm-up, followed by eight 2-min intervals of high intensity (>80 % of HRmax) followed by 2 min of moderate training intensity (60 % of HRmax), and 5 min of cool down. Tolerability was assessed by investigator consensus using a decision guiding framework based on attendance, incidence of knee pain flares resulting in non-compliance with the HIIT program during the 12-week period and change in knee pain (0–10 scale) at session start from the first to the last week of the program.

The average Borg Rating of Perceived Exertion (RPE) score during intervals was 16.2 (SD 1.2) over the 12 weeks. Average attendance to sessions was 88 %. The prevalence of knee flares increased from 3 to 5 from the first to the last 6 weeks, and the number of participants with ≥1 point knee pain reduction from week 1 to week 12 was 19 (46 %). According to KOOS thresholds, participants had mild difficulty in Pain, ADL, and Symptoms; moderate difficulty in Knee-related Quality of Life; and moderate-to-severe difficulty in Function in Sports and Recreation.

In conclusion, the HIIT program appeared tolerable for most individuals with knee OA and elevated CVD risk including those with mild-to-moderate difficulties in pain, function, and quality of life, supporting its potential feasibility in this clinical population.