Keeping a weight training log is one of the most results producing endeavors the average gym-rat can undertake. Sadly, however, is the fact that few, if any keep a log. I can only imagine that such complacency is due to ignorance of the benefits and how-to of keeping a training log.
Among the benefits of keeping a log include ensuring accuracy, ability to review efficacy, and motivation. Such benefits allow for enhanced progression. Furthermore keeping a good training log can be as simple as logging dates, resistance, reps, and sets.
Ensuring accurate stimulus
Keeping a training log ensures stimulus accuracy. Without record of the weight and reps you perform, you often, inadvertently, present the wrong stimulus to progress. For example, most people pick a range of weights and take each set until failure assuming simply repping to the limit is sufficient for progress. What if, however, your goal is strength and, because there's no record, you just rep to the limit with the weights your buddy's using. If your buddy's weights allow too many reps (at lesser force of course), you might have altered your nervous system to reduce recruitment to accommodate those extra reps the next workout.
We all have periods of training that are more and less productive. Among the factors that contribute to having more gaining periods than stagnant periods is the ability reproduce the gaining periods. Merely remembering the weight/sets/reps of such a period won't suffice for long. As one becomes more advanced, reproducing the training period that preceded the gaining period is often necessary to truly reproduce the gaining period. Without a log of training history, it's very difficult to reproduce multiple training periods accurately.
In addition to accuracy, a training log amplifies motivation. Consider how much harder you push yourself at something when you're being compared to a given standard. Most of us amp-up our efforts in such situations. A good way to continually access that type of motivation during training is to compare your current self with your previous self. Having record of your previous self's performance allows for such motivating comparison.
How and what to log
Initially, all you need to record in your training log is the date, load, reps, and sets of each exercise. Entering the date of each workout is important because it allows you to see the type/amount of rest and training between workouts that improves/hinders progression. Retaining records of the load, reps, and sets is important for knowing the intensity and volume of the work you're doing so you're truly progressing under conditions that are equal/more demanding than before.
The nutshell of a weight training log
Keeping a weight training log is probably one of the most effective, yet under-utilized practices engaged in by fitness enthusiasts. Maintaining records of your workouts ensures accuracy and consistency of the training stimulus while also providing renewable motivation for continual progress. Additionally, a weight training log is as easy as recording the dates load, reps, and sets of your exercises.