As we've mentioned before, after practicing sound nutrition principles, resistance/strength training is the most effective and efficent way to chan...ge both how you look AND feel. Mastering your own bodyweight, kettlebells, and free-weights are the 3 main ways to strength train. For those looking to get started, and even those who 'already know what they are doing', the following resources are some of the best in explaining the finer points of performing exercises CORRECTLY.
They also serve as a great head start or introduction before attending your first class at Pittsburgh Kettlebells.
Bodyweight: Convict Conditioning - Paul Wade
Free Weights: Starting Strength - Mark Rippetoe
Kettlebells: Enter The Kettlebell - Pavel Tsatsouline