The ones I use most often are the #5 Progressive Overload Principle, #10 Superset Principle, and #14 Staggered Sets Principle.
Weider didn't invent any of these principles. He did compile them which is a good thing.
https://www.trulyhuge.com/the-weider-principles.htmlPRINCIPLES TO HELP YOU PLAN YOUR TRAINING CYCLE
1) Cycle Training Principle (Breaking your training year into cycles for strength, mass or contest preparation you help avoid injury and keep your body responsive to adaptation)
2) Split System Training Principle (Breaking your workout week into upper versus lower body training, for example, results in more intense training sessions).
3) Double or Triple Split Training Principle (Breaking your workout down into two or three shorter, more intense training sessions per day).
4) Muscle Confusion Principle (Muscles accommodate to a specific type of stress ("habituate" or "plateau") when you continually apply the same stress to your muscles over time, so you must constantly vary exercises, sets, reps and weight to avoid accommodation).
5) Progressive Overload Principle (The basis of increasing any parameter of fitness is to make your muscles work harder than they are accustomed to).
6) Holistic Training Principle (Different cellular organelles respond differently to different forms of stress, so using a variety of rep/set schemes, intensity and frequency will maximize muscle mass).
7) Eclectic Training Principle (Combining mass, strength or isolation-refinement training techniques as your instincts dictate into your program often help you achieve greater progress).
8 Instinctive Training Principle (Eventually, all bodybuilders instinctively attain the ability to construct diets, routines, cycles, intensity levels, reps and sets that work best for them).
PRINCIPLES TO HELP YOU ARRANGE YOUR WORKOUT
9) Set System Training Principle (Performing one set per bodypart was the old way; the Set System calls for multiple sets for each exercise in order to apply maximum adaptive stress)
10) Superset Training Principle (alternating opposing muscle group exercises with little rest between sets)
11) Compound Sets Training Principle (alternating two exercises for one bodypart with little rest between sets).
12) Tri-Sets Training Principle (Doing 3 exercises for one muscle group with little rest between sets).
13) Giant Sets Training Principle (Doing 4-6 exercises for one muscle group with little rest between sets).
14) Staggered Sets Principle (injecting 10 sets of boring forearm, abdominal or calf work in between sets for (say) chest or legs).
15) Rest-Pause Principle (using 85-90 percent of your max, do 2-3 reps and put the weight down. Then do 2-3 more, rest, 2-3 more and rest for a total of 3-4 rest-pauses. The short rest-pauses allow enough time for ATP to be resynthesized and permit further reps with the heavy weight).
16) Muscle Priority Principle (Work your weaker body parts first in any given workout; alternatively, work the larger muscle groups first, while you're fresh and energy levels still high).
17) Pre-Exhaustion Principle (example: superset flies, a chest isolation exercise, with bench presses, a compound exercise involving triceps and chest, in order to maximize chest development by pre-exhausting the triceps).
18) Pyramiding Training Principle (start a bodypart session with higher rep/low weight and gradually add weight (and commensurably reduce the reps), ending with a weight you can do for 5 reps or so).
19) Descending Sets Principle (lighter weights from set to set as fatigue sets in --0 called "stripping").
20) Staggered Sets Training Principle (stagger smaller, slow-developing body parts in between sets for larger muscle groups).
21) Instinctive Training Principle (Eventually, all bodybuilders instinctively attain the ability to construct diets, routines, cycles, intensity levels, reps and sets that work best for them)
PRINCIPLES TO HELP YOU PERFORM EACH EXERCISE
22) Isolation Principle (All muscles act as stabilizers, synergists, antagonist or protagonist. By making any given muscle the prime mover in any given exercise you've "isolated" it as much as possible, and therefore the stress applied to it)
23) Quality Training Principle (gradually reducing the rest between sets while still maintaining or increasing the number of reps performed)
24) Cheating Training Principle (swing weight past the sticking point at the end of a set in order to add stress).
25) Continuous Tension Principle (maintain slow, continuous tension on muscles to maximize red fiber involvement).
26) Forced Reps Training Principle (partner-assisted reps at the end of a set)
27) Flushing Training Principle (Doing 3-4 exercises for a bodypart before moving to another bodypart).
28) Burns Training Principle (2-3 inch, quick movements at the end of a set).
29) Partial Reps Training Principle (Because of leverage changes throughout any given exercise, it's sometimes helpful to do partial movements with varying weight in order to derive maximum overload stress for that bodypart).
30) Retro-Gravity Principle ("Negatives" or "eccentrics" as they're called, make it possible to get more muscle cells to respond because you can lower about 30-40 percent more weight than you can successfully lift concentrically).
31) Peak Contraction Principle (holding the weight through maximum contraction for a few seconds at the completion of a movement)
32) Superspeed Principle (compensatory acceleration of movements to stimulate hard-to-reach fast twitch fibers)
33) Iso-Tension Principle (method of practicing posing, tensing each muscle maximally for 6-10 seconds for up to a total of 30-44 flexes in a variety of posing positions).
34) Instinctive Training Principle (Eventually, all bodybuilders instinctively attain the ability to construct diets, routines, cycles, intensity levels, reps and sets that work best for them
