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Sensing Technologies for Real-time Mistake Detection & Corrective Feedback for Free-Weights Exercises

Technology Overview

We present ERICA, a digital personal trainer for users performing free weights exercises that relies on low-cost inertial sensors. ERICA has three key differentiators: (a) First, unlike prior approaches that either require multiple on-body wearables or specialized infrastructural sensing, ERICA uses a single in-ear “earable" device (piggybacking on a form factor routinely used by millions of gym-goers) and a simple low-cost inertial sensor mounted on each weight equipment; (b) Second, ERICA is able to identify a variety of common-place fine-grained exercising mistakes and deliver real-time, in-situ corrective instructions; (c) Finally, ERICA provides such personalized feedback to users exercising either alone (e.g., at home) or in a shared space (e.g., gym).

Technology Features, Specifications and Advantages

Our technology supports fine-grained tracking of an individual’s exercise via a combination of (a) sensors on personal wireless ear-worn devices (‘earables’) and (b) inexpensive inertial sensors attached to non-personal exercise equipment. The choice of the earable is key to the practical appeal of our technology: (i) it is the most popular and rapidly growing wearable device and widely used while workouts, thereby significantly lowering the adoption barrier, and (ii) it can directly support the delivery of audio-based feedback to individuals in a private manner.

Our technology features the key properties below :

  • Dynamic multi-user, multi-equipment support
  • Unobtrusive, low-cost instrumentation
  • Fine-grained mistake detection
  • Timely and personalized feedback

Real world studies show that ERICA can :

  • Robustly handle scenarios with multiple (even 15) concurrently exercising users
  • Identify the exercise performed with 96% accuracy
  • Identify 94.4% of mistakes early (during the first 5 repetitions), thereby supporting in-situ feedback during an exercise set.

We have experimentally demonstrated that ERICA-based feedback is favored by ~80% of users and reduces the incidence of exercising mistakes by 10+% mistakes.

Potential Applications

This technology can be used in a “Digital Personal Trainer” application that can perform advanced analytics to provide personalized real-time feedback. Such an application can reveal, for example:

  • Is the user making mistakes while performing exercises? For example,
    • is the user performing full range of motion of lateral raises exercise?
    • Is the user swinging his body while doing bicep curls?
  • Is the user training the same set of muscles repeatedly across different sessions? The application can then suggest more variety of exercises and also specific areas that a user need to improve.

Our technology is part of an emerging suite of Digital Wellness technologies and can be employed in the Wellness & Healthcare industry, both at home and in shared gyms.

Customer Benefit

ERICA’s simple, cost-effective and unobtrusive approach allows users to obtain the benefit of real-time quantified fitness tracking and feedback, thereby significantly improving workout engagement and effectiveness.

  • Gym-goers will be able to track their exercise routine (exercises, number of sets/repetitions, quality of execution), progress and performance. They can obtain personalized coaching from a “virtual trainer”, which identifies mistake in exercise execution and provides corrective feedback. This is much cheaper than using human personal trainers.
  • Gyms and activity centres can offer their users valuable personalized feedback at low cost, thereby increasing customer engagement and increasing retention.
  • Mobile and wearable App developers can integrate gym activity into upcoming wellness and healthy living Apps.
Contact Person

Francis Lim


Singapore Management University - School of Computing and Information Systems

Technology Category

  • Infocomm
  • Healthcare ICT, Internet of Things & Wearable Technology

Technology Readiness Level


Earables, Internet of Things (IoT), Smart Gym, Digital Personal Trainer, Free-weights Exercises, Personalized Feedback