Whoop's muscular load measurement will change fitness tracking as we know it
Strength Trainer, a feature that allows Whoop 4.0 users to track weightlifting exercises, measures musculoskeletal strain for the first time ever in a wearable.
Fitness trackers use a ton of different metrics to measure exertion and strain, but the majority of those metrics come from an optical heart rate sensor that detects your pulse. That works great for people who mainly do cardiovascular exercises, which push your heart and lungs in a way that is directly correlated to heart rate.
Weightlifting and other types of strength training doesn’t work the same way. It puts stress on your muscles and bones in short bursts during repetitions, and those reps are repeated through sets. The combination of short bursts of exertion and routine recovery periods means that your heart rate won’t experience the same level of sustained elevation as it would during cardiovascular exercises.
It’s only fitting that the company to finally address this discrepancy is Whoop, who are known for their in-depth fitness tracking metrics. When I reviewed the Whoop 4.0 in February 2023 for Screen Rant, I came to the conclusion that the Whoop was great for serious trainers with a specific goal — like running a marathon or trying to win a weightlifting competition. But with Strength Trainer, the Whoop 4.0 could become the default option for weightlifters of all skill levels.
How Strength Trainer measures muscular load
Strength Trainer was brought to all Whoop 4.0 devices in April 2023, and it uses sensors already within the wearable to measure musculoskeletal strain. In simple terms, it tries to figure out how much weight and stress is placed on your body during strength training exercises.
Strength Trainer works by creating workout regimens that include the number of reps, sets, exercises and weights. There are over 200 exercises in the Strength Trainer library at launch, but you can also create your own custom workout in the Whoop app. Then, the Whoop 4.0 will guide you through the workout in the companion app, using the gyroscope and accelerometer to measure muscular load.
These figures will then be incorporated into the Whoop’s daily strain score. Strain is measured on a scale of 0 to 21 and can be affected by factors like exercise, work, anxiety, running errands, parenting, and more, according to the company. There are four tiers of strain — light (0-9), moderate (10-13), high (14-17), and overreaching (18-21). These tiers are used to determine how much recovery a user needs, which is measured as a percentage out of 100.
Now that the daily strain score has a more accurate perception of strength training exercises, the Whoop’s industry-leading recovery features will give a better representation of your training.
Whoop is the first-ever wearable to measure muscular load
Whoop 4.0 quantifies muscular strain in tonnage, which in weightlifting is known as the total weight lifted during a given workout. So if you do 10 reps of an exercise moving 100 pounds, your total tonnage is 1,000.
What makes Whoop unique is that the company uses various factors to determine tonnage, including muscular response, volume and intensity of training. In doing so, they’ve become the first consumer wearable to measure muscular load.
Strength Trainer on Whoop 4.0 takes the guesswork out of measuring strength training exercises, which could be a game-changer for weightlifters. Now that a Whoop membership is as low as $239 for a 12-month membership, and a 24-month membership can be bought for $399, it’s an enticing proposition. Whoop continues to innovate, and is making their presence known in the fitness space.