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They’re both terms we hear a lot in the fitness world, and personal trainers use them almost every day among their classes and clients sessions… but what do they actually mean?! HIIT stands for “high intensity interval training” whilst LIIT stands for “low intensity interval training”. Let’s first of all break down the one thing that they both have in common; interval training.

Interval training is defined as “physical training consisting of alternating periods of high and low intensity” (definition from Oxford Languages), which may lead you to think… is there actually any difference in the training then? Well yes, is the short answer. HIIT training periods are very high intensity (think squat jumps, mountain climbers and high knees), whilst LIIT periods aren’t as intense, but generally stick to the same time frames (squats, lunges or crunches for example). In typical TABATA style HIIT (originated from Japan as an alternative to moderate long duration exercise), time periods are 20 seconds work with 10 seconds rest for 8 rounds (a 4-minute block), although you may find slightly different interval training periods in some classes, such as 30 seconds work and 15 seconds rest, but this of course won’t be classed as typical Tabata.

There’s a time and place for both styles of training within a fitness timetable, and I often find that within my own classes I can offer both styles to my clients. Some people love the burn, and being able to push themselves, whilst understandably, others may prefer a slower sweat, or need to take care with a current injury for example. Injuries don’t always mean complete rest - it's sometimes more beneficial to move gently than not at all, as we can otherwise lose strength across the whole body!

This isn’t to say that HIIT is better than LIIT in the sense of reaping the benefits, and that usually comes down to personal goals – not everyone’s goal is weight loss, so LIIT may be the preferred choice to create muscle endurance and the appearance of muscle tone. For women peri/post-menopause, weight bearing exercises are important, but care needs to be taken if a woman is new to the style of training, however LIIT can be a good option for these women. Equally, HIIT may be perfect for clients who want to notice a quick shred and improvement in power output – for more specific sports reasons, and for those who want to be able to push their fitness limits.

I always try to offer variations within my classes – I personally prefer higher intensity classes but I’ll still try to show my clients an alternative option for their training to ensure that they feel comfortable within class too. High knees jogging on the spot can be easily changed into marching on the spot, picking the knees up towards the chest and placing the foot down more gently. Squat jumps can be swapped out for a squat into calf raise, with the bottom reaching down to touch a chair. Full press ups can be changed to a press up on the knees, and even at an incline with hands up on the sofa.

Whilst I’ve only mentioned a few of the benefits from both HIIT and LIIT, I would highly recommend either of the training styles to be added into your fitness regime. If you’re lacking motivation, this is one of the easiest ways to get started… work for 20 seconds, knowing that you’ll soon have a 10-second rest, and you’ve only got to promise yourself to 4 minutes to start with. Once you’ve tried this short block, build it up on your next session to 8 minutes. Before you know it you’ll have built up to a full 30 minute class and you’ll most likely have noticed a huge improvement in strength as well as breathing rate and heart rate. Not sure where to start…? Give this quick set a go (Search AJR Personal Trainer on YouTube for more)

or head to my instagram post below for more ideas!

Happy Training all! AJR x

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