Body parts don't exist in isolation. Every muscle, joint, tendon, and bone is part of a system. Every athletic movement puts this system in motion. Therefore, it is necessary to train the system not the muscle. Compound exercises, movements that require multiple levers and joints to work together, build better and more efficient athletes.
Compound exercises engage more muscle groups, which allows you to lift more weight, which translates into faster more consistent progress. Isolation exercises, movements that focus on moving a single joint through a range of motion, target only one muscle group at a time which means you will be lifting less weight and progressing more slowly.
What do you think will make you potentially faster, adding 100 pounds to your squat or 10 pounds to your bicep curl?
Sprinting fast is a very coordinated and complex task. Your body must go through a very precise and specific sequence of movements at very high speeds and loads. Performing the right compound exercises in the weight room will reinforce these movement patterns and enhance muscle memory.
Stop wasting time. Speed up your progress by replacing isolation exercises with compound exercises.
Replace Calf Raises with Step Ups
Calf muscles are the link between your quads and your feet. The primary purpose of the calf muscles is to transfer energy between the feet and the quads. The speed of this transfer of energy is elicited through the stretch shortening cycle.
Calf raises, an isolation exercises, build and pump the calf muscles which limits how effective they can be at utilizing the stretch shortening cycle to deliver energy either to the ground or to the quads and hips. Pumped calf muscles also limit ankle range of motion and make you more prone to injury.
Instead of explicitly targeting your calf muscles, train the entire hip, knee, ankle system. Your calf muscles will develop naturally as a by product of squats, lunges, step ups, jumping, and sprinting.
Replace Bicep Curls with Pull Ups
I can't think of any interscholastic sport that requires you to pull anything heavy with just your biceps. Most of the time the larger and stronger muscles of your back are doing the majority of the work. Big biceps may look good at the beach, but they don't enhance your athletic performance.
Instead of bicep curls, do pull ups. Pull ups using a variety of hand positions (neutral, wide, narrow, inward or outward facing) not only target your entire arm, but also hits the major muscles of your back that are going to support nearly all athletic movements.
Replace Shrugs with Deadlifts
Shrugs isolate the trapezius muscles in the upper back and lower neck. While they are important muscles to support the head and neck, they work in concert with all the other back muscles to keep your head up and spine in line. Plus, if you are a spending a lot of time hunched over a book and computer these muscles get tight.
Instead of getting in somebody else's way on the squat rack doing shrugs, deadlift! The deadlift is a compound movement that works a variety of muscles groups---maybe even the most muscle groups. Take a look at the Wikipedia entry on the deadlift and see for yourself all the muscles involved.