There appears to be a certain hotspot where endurance correlates with one’s strength level. When discussing compound lifts, Zatsiorsky stated in his work Science and Practice of Strength Training that this equates to roughly 25% of one’s 1RM (one repetition maximum on a given exercise).
In other words, if we were to take two athletes of similar bodily structure and one of them can squat 200 kg while the other can squat 150 kg, we can with near certainty state that the 200 kg squatter can perform more repetitions at values over 25% of their 1RM. (The 200 kg squatter will experience less fatigue than the 150 kg squatter when performing multiple repetitions at, say, 70 kg.)
On the other hand, if we were to instruct both athletes to squat 20 kg for maximum reps (which is under 25% for both of them), it would be impossible to say who could endure more reps. From a logical standpoint, this makes sense—otherwise, all endurance athletes, regardless of sport, would probably get away with strength training alone.
With such reasoning, it may be argued that the more athletes have to endure fatigue under loaded conditions, the more beneficial strength training will probably be when it comes to endurance.
Strength and wrestling-endurance
How can this concept be applied to one’s sport? Let’s take wrestling as an example.
A wrestler will constantly be going against the resistance of his opponent. (Which will sometimes correspond to values dramatically above 25% of one’s strength level.) During a wrestling match, one will not be lifting barbells; one will be in a dynamic grappling situation. And strength in such a scenario is much more complex than merely a 1RM in a squat—the concept itself, however, gives us valuable insight. (The value of 25% is a rough estimate that will vary greatly depending on the specific situation.)
Let’s take a hypothetical scenario of two wrestlers with similar bodily proportions, skill- sets, mental toughness, etc. They will be leaning against each other, lifting, pushing, ripping, pulling, and doing all kinds of grappling maneuvers. In other words, they have to overcome resistance for extended periods of time in very demanding conditions. (The bodyweight of the opponent and the forces the opponent produces in addition to that.)
One of the wrestlers, however, is two times stronger (in terms of raw muscular strength in all planes of movement). In a situation like this, the stronger wrestler would get less tired than his weaker counterpart because his ceiling for strength is higher. And anything moderately below that ceiling equates to less energy required (as explained in our previous point). This is a practical example of where endurance correlates with strength.
Therefore, for a wrestler, it would be wise to train aspects of endurance under loaded and powerful conditions. This can be done with circuit training (anaerobic endurance) and specific days for strength training (anaerobic power). This will all lead to a well-developed lactate threshold, buffering capacity, and improved motor-unit recruitment. But as a matter of traditionalism, there is still an outdated notion that wrestlers are supposed to prioritize lengthy aerobic endurance sessions (and underprioritize anaerobic formats).
If you have two wrestlers of equal physique and skill, and one of them approaches muscular endurance training with high resistance (anaerobic), he would win. It wouldn’t matter if the other wrestler could do a triathlon or run a marathon; this does not correspond to the endurance experienced in wrestling.
In contrast to what we have discussed so far, a marathon runner would obviously prioritize extended endurance sessions at a relatively steady pace and various intervals, because that is what the sport requires. In such a scenario, this hotspot where strength correlates with endurance is almost nonexistent. As a secondary priority, however, the marathon runner would implement strength-training for tissue strength, injury prevention, and possibly running economy.
Endnote
A freestyle wrestling match consists of two periods of 3-minute rounds (with 30 seconds of rest in-between). As we have previously discussed, wrestling consists of intervals of vigorous activity.
Knowing what we have to prepare ourselves for, what would be the right course of action? To analyze what happens in a wrestling match—both movement-wise and metabolic-wise (energy systems). This does not require a prestigious degree; only a shred of common sense.
Now what is the point of doing strength and conditioning? It is to isolate a specific component that would otherwise be hard to emphasize in the sport itself. We are not striving to copy the exact movements that occur within a sport (otherwise there would be no use in implementing S&C).
And strength training (the point of this article) isolates the aspect of just that: strength (maximal force production). It is one piece of the puzzle that makes up the necessities of a wrestler. If I can front squat a weight of 160 kg, chances are, it will correlate positively to my ability to lift my opponent—who may not only weigh half of that but may also possess lower strength than me. In other words, I will get less tired from grappling with my opponent (who is significantly below my celling of strength)—indirectly leading me to have superior endurance in such a situation.
Source
Zatsiorsky, V. M., Kraemer, W. J., & Fry, A. C. (2020). Science and practice of strength training. Human Kinetics.