There are two main reasons that I commonly see that stop athletes from performing at their best in their chosen sport.
Strength is the main thing holding many people back. Let’s take a rugby league player as an example. They could have all the skill in the world but if they are not strong enough to break the defensive line and get quick play the balls or make dominant tackles then all their skill doesn’t really matter. They have too many deficiencies in their game to be at the top of their sport. They could be trying their hardest to be effective in defence but until they address their poor strength levels they will be spinning their wheels.
The strongest athletes also tend to be the fastest. In sport, speed is everything. It gives athletes confidence knowing they can get to positions on the field no one else can, and it can also make a good player, a great player, by being able to take opportunities others can’t. They turn half breaks into breaks and score points out of nowhere. They save points by running other players down. It is an attribute that every coach wants in their team.
A strong athlete tends to miss fewer games due to injury. If an athlete is strong they tend to work on their imbalances in the gym as they are more aware of what they need to progress and what areas are under par. They seek professionals to help them reach their best and then do the work. Another thing about having strong muscles is that if you are injured, they tend to return to health a lot quicker than an untrained or weak muscle.
Many strength coaches would have heard the saying “strength is the mother of all physical qualities”. This is because strength levels are the foundation for everything else. If you want to jump higher, run faster, hit harder, then strength will help you do all these things better. With all other factors being equal, the stronger athlete will win.
The second reason why athletes don’t reach their potential is due to poor conditioning levels. You may have all the attributes you need to be successful in your sport such as skill and strength levels, but if you are unable to repeat high quality efforts then eventually you will get found out. Let’s say you do jiu-jitsu, you could be strong and unfit and still win as long you had the skill to back up your strength and finish opponents quickly. If however, you come up against someone of equal strength and skill and you have to go the full length of a fight, then you better have enough conditioning to be able to explode and repeat high quality movements or you will be beaten. Also, you have multiple fights in a competition so you have to be able to recover between fights quickly enough to compete at your best each fight.
In rugby league, if you can’t get back on side, set line speed, work from the inside in defence, continually get caught on the ground instead of making it to marker, you are pretty much useless as the other team will work to exploit you in no time. Same goes with your hit-ups. One good explosive hit-up may look good on your highlight tape but it is really how consistently you can do it. How often can you dent the other team’s defensive line and get quick play the balls for your team? That is what counts.
I say conditioning instead of fitness or endurance as I see those a general preparation. Conditioning is more specific. It is being able to repeat the demands of you sport. For example you could improve your rowing time of a 1500m effort which would increase endurance but as a rugby league player it won’t necessarily improve your on field conditioning or performance. Making repeat tackles or doing forms of wrestling will.
Why in this order?
I look at strength as number 1 because if you aren’t strong then you are already behind. You may have superior conditioning but if your opponent is super strong, fast, and explosive, and crushes you in the first 30 seconds, all of your conditioning doesn’t matter at all. You would have to find a way to tire out the stronger opponent first to have a genuine chance.
Also strength levels can help endurance levels but the reverse is not true. So if you get stronger you can still increase your conditioning. That is why I would prioritize strength over conditioning if I had to decide. If you focus on conditioning as your priority you won’t be able to get as strong as possible.
As always it is individual as to what your priority will be. If you already match the strength norms for your sport and your conditioning sucks, then you would put your strength training to maintenance levels and focus on your conditioning. Like Charles Poliquin says, there is an optimal level of physical qualities (strength, conditioning, flexibility, etc.) needed for every given sport, not always a maximal level. A rugby player doesn’t have to be as flexible as a gymnast but they still need some flexibility.
Think about what you need. You may have been doing the same thing over and over expecting a different result, when what you really need is a different approach. What is limiting you?