FITNDEX began in 2020, during the national COVID-19 quarantine, with a simple question: how much harder is a squat day than a bench day?

Like many people at the time, our founder, Steven Srivastava, began training at home with a basic setup: a barbell, a bench, and a few plates. Over time, that setup grew into a more complete basement gym with a deadlift platform and squat rack, making it possible to train all three power lifts consistently.

As his training became more structured, he noticed something unusual. Intense squat and deadlift sessions often left him with a feeling of brain fog, while bench press and overhead press days did not. At first, the assumption was that the effect might be tied to intensity or power output. But when the same feeling showed up after long runs, that explanation no longer held up.

That led to a different idea: maybe the issue was not power, but total work.

From there, the question became more specific. Could the amount of work performed during different types of exercise actually be measured in a meaningful way? And if so, could that help explain why certain sessions placed a different kind of demand on the body and mind?

The first step was to compare the mechanical work of a squat session versus a bench press session. Measuring the barbell was relatively straightforward. With a measuring tape and some basic observation, bar displacement could be estimated with reasonable accuracy. The real challenge was accounting for the movement of the lifter’s body, especially during exercises like the squat, where a significant portion of the work is not just moving the bar, but moving the body itself.

That problem required something more sophisticated than a simple top-and-bottom measurement. It called for center-of-mass estimation, positional modeling, and a way to account for how body segments move through space during an exercise.

So the work moved into a spreadsheet.

What began as a personal effort to understand training fatigue gradually turned into a modeling problem: how to estimate mechanical work, and eventually power, across different movements in a way that was both practical and individualized. Over time, methods emerged that made these calculations increasingly reliable.

Alongside that work came a broader realization: physical output is only part of the picture. Through repeated personal experimentation, it became clear that training response also seemed to be influenced by factors such as recent nutrition, training volume, and intensity. In particular, one working hypothesis was that the mental fog followed periods when the body appeared to be transitioning away from readily available glucose and toward a different metabolic state. While these observations were anecdotal, they helped sharpen the core insight that exercise demand is deeply real, measurable, and highly dependent on context.

The real breakthrough came when exercise comparisons started extending beyond barbell lifts. In one early experiment, a burpee was estimated to require roughly five times the work of a pushup for one individual. But when that same comparison was tested with other people, the ratio changed.

That finding became foundational.

There was no universal conversion factor between exercises. A rep is not just a rep, and the cost of movement is not identical from person to person. Each individual expends a different amount of energy per repetition, per exercise, based on their body and mechanics.

That insight became the basis for FITNDEX.

What started as a personal attempt to understand training stress evolved into a broader mission: to create a system that can evaluate exercise performance in a more measurable, personalized, and meaningful way. FITNDEX exists because comparing human performance is possible — but it requires better models, better metrics, and a better understanding of the individual behind the movement.