Strength Endurance – The ability to maintain muscular force over a period of time (i.e. developed with movements like Lunge hold performed for 3-5 minutes, 300 repetitions of a Cross-Crawl Supermans with intent, etc.)
Maximal Strength – Actual strength output (1-rep-max (1RM) of a lift)
Relative Strength – Amount of force created per pound/kilogram of bodyweight (1RM divided by body mass)
Isometric Strength – Maximal force generated without change in muscle length/against an immovable object (manual holds, or, as an example, maximally bench pressing bar up into immovable pins)
Eccentric Strength – Yielding strength (i.e. “negative” or “lowering” portion of a movement causing muscle to lengthen. This is the case in most holds done properly as you “pull” down into the greatest range of motion and fatigue to greater joint angles)
Absolute/Potential Strength – Main factor determining the speed of a movement (i.e. reason why a dude is still really fast in one sprint despite not training/sprinting in months)
Explosive Strength – Creating a high amount of force in a short time (developed primarily through plyometrics)
Starting Strength – Ability to quickly begin producing force (beginning of a concentric contraction without an eccentric contraction beforehand)
Acceleration Strength – Ability to quickly reach maximal force (catching and repelling falling loads, a la “Rebounds” and “Altitude Drops”)
“What type of strength do I need?”
For all humans, strength endurance (the ability to maintain muscular force over a period of time) is, in my amateur opinion, the most important and what needs to continually be added to in the foundation.
Strength endurance can be quantified in a lot of different ways, but more generally speaking, all injury is caused by the body’s inability to absorb force. With muscles acting as the primary force absorber in the body, they must be able to turn on and do their job on their own (independently) and with their neighboring muscles (inter-dependently) for prolonged and sustained periods of time. To build other “types” of strength without a huge base of strength endurance is like putting a sports car engine in a golf cart. Building a huge foundation, honoring the amount of time that it takes (years), and continually adding to it will allow you to do your activity, hobby, or sport of choice in a safer manner and at a higher level.