Exercise is great. Any exercise is generally better than no exercise, and people worry too much about optimization. That is, worrying about finding the perfect program is less important than choosing any program aligned with goals and sticking with it. The Internet is full of boring "one secret tip" and "if you could only do one exercise" articles. These articles aren't interesting because they aren't realistic. You can and should do more than one exercise.
Novice athletes benefit the most from building a foundation of strength and mobility. Endurance is easy to lose and easy to gain, but returns from endurance training diminish quickly. Strength, on the other hand, can repeatedly double for several years. It is not uncommon for a young athlete to bench press 135 pounds after only a few months after initially struggling with the bar. These strength gains can continue (though at a diminished rate) for several years.
I agree with CrossFit's doctrine of constant variation, functional movement, and high intensity in preparation for the "unknown and unknowable." I believe that technique is important, but I also believe that the overall goal of the workout should dictate just how strict one needs to be. For example, the 300 air squats in Murph can stimulate hypertrophy, fat loss, and endurance even if athletes can't squat to parallel. They probably won't do much for strength, which is why it is important to state the purpose of an exercise before attempting it.
Barbells are wonderful. They are extremely versatile, inexpensive, durable, and relatively easy to transport and store. Contrast a barbell set to single-purpose and expensive exercise machines and fixed-weight dumbell racks. Consider also that the plates can be reused with sleds, ropes, bags, belts, and the like for a creative exercise. A barbell set, with a basic squat stand and bench, is all a garage gym needs.
Calisthenics are complicated. On one hand, calisthenics are appealing because most require no or minimal equipment and are easy to teach. On the other hand, calisthenics can be difficult to scale or practice when an athlete is incapable of performing one correct repetition. We can always find a broomstick for a novice athlete who cannot bench press the bar, but what should we do for an athelete too heavy or too weak to perform a single push-up? Furthermore, many calisthenics offer little to the advanced athlete who has mastered an exercise. Consider a gymnast who is very good at pull-ups. What can the gynmast do to get better at pull-ups (without adding equipment)? The obvious answer is to just do more pull-ups, but this approach will diminish returns and accumulate stress.
This list of bad exercises describes movements that I believe either provide minimal value or are actually harmful. For each bad exercise I propose an alternative exercise that I believe safely delivers more value. A common theme throughout is that the squat, bench press, deadlift, overhead press, kettlebell swing, farmer's walk, pull-up/chin-up, sprint, tire flips, and sled push/drag are compound (multi-joint) movements that deliver real results because they employ your body as a system.
This bad exercise is popular in the military. Stand with arms held outwards, parallel to the ground, with the palms supinated. Raise the arms with elbows locked in place and clap overhead. This exercise can be repeated hundreds of times. It is painful and tiring to the deltoid muscle. Unfortunately, one never gets appreciably better at this exercise. The shoulder is the most mobile joint in the human body and has very complex musculature. Shoulder injuries are common in sports and on the job, so it is very important to build strong shoulders. The overhead arm clap is not a good way to do so. The best shoulder exercise for the novice athlete is the standing overhead press. The press can be performed with a barbell, dumbell, kettlebell, or really anything heavy you want to put over your head. Heavier is better. Overhead exercises should never be spotted, as people have a knack for getting out of the way before something squishes their skull.
The previous paragraph recommended the standing overhead press for a reason. Consider a typical chair. The seat is about two feet off the ground. Would you be willing to jump this height and land on both feet? Of course you would. Would you be willing to slide off of a chair and land directly on your buttocks? Probably not, as this sounds painful and dangerous to the spine. So why would you load a bar and let that weight smash your pelvis without transferring through the femurs? Furthermore, the seated press allows the athlete to let the chair lock their spine and hips. You might be able to press more weight while seated, but this is because the abs, glutes, and quads (the "core") are not providing the stability they're supposed to. The standing press does a better job to use the body as a complete system. Finally, are you going to push boxes to the attic from a seated position? Probably not. Everyone should press, and everyone should press from their feet.
Everyone should be capable of holding a plank for a minute or two. If you cannot then it is probably worth practicing planks for a couple weeks and learn to brace the core. On the other hand, once you master a two minute plank then there isn't much more you can get out of this exercise. There isn't any benefit from holding marathon planks and this position is difficult to load with more weight. Bracing the core is a very important skill and you can continue to brace better by adding weight to the squat, press, and with heavy farmer's walks.
High risk, low reward. This variation on the bench press seeks to isolate the tricep. From a supine position, lower the weight to the forehead by hinging only at the elbow with humerus basically vertical. This exercise succeeds in isolating the tricep and can lead to a nice "pump." Unfortunately, athletes usually do this with much less weight than they would bench press. Humans are descended from quadrupeds that used these muscles constantly while walking. Just as the quadriceps need no endurance training but benefit most from strength training, the tricep and chest benefit most from very heavy loads. You can only push the heaviest loads by using your muscles together as a system. Therefore, the bench press is a superior exercise for working the chest and triceps. Skullcrushers might be a viable assistance exercise for more advanced athletes, but novices won't benefit from this. Beginners needs to focus on the big lifts and not get distracted with low reward exercises like the skullcrusher.
Tricep extensions are usually performed with sophisticated cable machines. The cable machine is usually mush larger, much more expensive, much less durable, and much less versatile than a barbell set. If I were a gym owner I would not have one of these things at all. The cable machine is not useful, and many bodybuilders find it useful to develop specific muscles in isolation. This document is not written for such people. As an isolation exercise, the tricep extension has all of the same flaws of the skullcrusher. Just press overhead, bench press, and do dips.
When I weighed 112 pounds I, too, stood in front of the mirror curling 15 pound dumbbells in hopes of one day getting bigger. Years later I discovered the deadlift, and lo and behold I actually got bigger. Bicep curls are probably among the most popular exercises in the world, but they're also among the least beneficial exercises in the world. If you tried to pull a tree stump out of the ground would you try to use your bicep at all? Probably not. Your body would immediately realize it was "leaking" force through the bicep and instead let the elbow fully extend, orient the spine in line with the direction of force, and push as hard as possible using the quads and glutes. Perhaps the strongest case for a strong bicep in nature is climbing, but even rock climbers will tell you that you climb on your feet and not with your hands. Functional fitness training will give you strong and beautiful biceps as a side effect of working the entire body as a system, with such exercises as the deadlift, pull-up/chin-up, tire flips, heavy carries, and heavy drags incidentally taxing the bicep as you hold on. This brings us to a nearby muscle that deserves more attention than the bicep — the hands. Our modern world of cars and elevators requires much less grip strength than that of our ancestors. Much like the bicep, train the hands incidentally through full-body functional movements. Also, take your friends or family to an indoor rock climbing gym once in a while.
Grip strength is important, but the wrist curl is not a good way to build it. The wrist is capable of curling, but there aren't many situations in life where the wrist curls a heavy load without getting any assistance from the arms, shoulder, back, and legs. There are three types of grip strength: support, crushing, and pinching. Train all three with the deadlift and pull-up. A thicker bar is more difficult to hold, so feel free to wrap the bar with a towel, Fat Gripz, or use an axle bar to make the traditional lifts harder. Hand trainers, such as a Gripmaster or hangboard, can provide useful assistance exercise outside of the gym.
The side bend is generally performed standing with one hand loaded with dumbbell, kettlebell, or plate. The athlete extends their spine in the coronal plane with the hips fixed. Most athletes won't attempt this exercise with enough weight to put themselves at risk. The problem with this exercise is that it simply fails to produce the result people expect. Many athletes who use side bends do so in an effort at "spot reduction." Their thinking is that exercising a muscle group near unwanted adipose tissue will burn that fat. The fitness community is divided on whether spot reduction is possible at all; the majority opinion is that spot reduction does not work. If the goal is to burn fat, athletes will benefit more from high-intensity interval training (HIIT). An example HIIT workout is to sprint six laps around a 400 meter track, resting for three minutes between each lap. If the goal is to build oblique strength then the athlete should try banded Pallof presses and single-arm farmer's walks.
Next time you squat, try to find out what your 1RM calf raise is. It's probably a lot. A whole lot. A whole lot more than you could squat, but only through a short range of motion. Of course, no one trains the calf this way. People are more likely to use a plate to raise the toe and allow the heel to dip into an extended range of motion, then repeatedly subject the calf to hundreds of painful repetitions. Amazingly, the calf never seems to hit "muscle failure" like one experiences with, say, a pull-up. Bodybuilders have historically found that the calf is difficult to hypertrophy (without steroids). I ask why anyone should bother. If the calf is already very strong and already has marvelous endurance then what benefit does direct calf training deliver to the athlete? Do stronger calves win fights in the ring? Do they move heavy things at the shipyard? Do they help you swim to safety? Not really. Strong calves do contribute a little bit to a heavy squat, but I have never heard someone say "I tried to PR my squat today but I missed because my calves couldn't take it." The activities where calves noticeably contribute are sprinting and hiking uphill. For these, I recommend buying minimal running shoes or barefoot running. For those who grew up heel-striking, learning to run on the midfoot is painful and takes time. It took me two years to finally feel comfortable midfoot running in my New Balance Minimus shoes. I have always been a competent runner, but the first time I earnestly tried a midfoot strike my calves were so sore I couldn't run again for six days. A safe progression for midfoot running is to run barefoot and simply stop when it becomes uncomfortable. It may take many months, even a year, to build up to running like a human, but the benefits will last a lifetime — unlike calf raises. Bicycling is also a useful exercise for training the calf.
Every gymbro loves shrugs. You grab the two heaviest dumbbells your hands can hold onto and watch yourself in the mirror bringing your shoulders at close to your ears as you can. This exercise is fun because you get to use much larger weights than you can curl or press. This exercise is useless because you'll never repeat this movement outside of the gym. The trapezius plays the same supporting role as the bicep and wrist when you carry heavy things. You certainly want strong traps, but the you won't get them from using them in isolation. You get strong traps from employing them in compound motions where many muscles work together as a system. Zercher exercises are very useful for this. Load a heavy barbell in the elbows and squat it. The hands should be balled into fists near your face. If you start with the bar on the floor then this is a Zercher deadlift. If you start with the bar in a rack at chest level then this is a Zercher squat. Zercher exercises deliver a unique challenge to the traps, scaps, and lats. Farmer's carries are another functional alternative to the shrug.
All of the exercises listed so far are simply inefficient. The upright row is actually harmful. Many athletes use this exercise on their "arm day" to supplement their pull-ups and bicep curls. The upright row is a standing barbell exercise where the bar is lowered to the hips and raised to the clavicle with a double overhand grip. The elbows flare out as the shoulder internally rotates at the top because this position puts the shoulder into impingement. The upright row is an unsafe exercise that should never be performed at all. Do pull-ups and chin-ups instead. If you are not strong enough to perform one pull-up or chin-up then you should learn to do so. A Gravitron is among the few useful Nautilus machines ever built; the Gravitron has a platform to push against an athlete's body, assisting them with pull-ups and dips. If your gym does not have a Gravitron then you should practice for a pull-up with: eccentric-only pull-ups (start at the top and let yourself down slowly); isometric hangs; and straight-arm pulls (pull only at the latissimus dorsi).
A leg press machine has a seat angled upwards and a sled fixed to a rail. The sled is pushed by the user's feet at a fixed angle. The leg press stresses the quadriceps, glutes, and hamstrings andis used as an assistance exercise to the squat. Ordinary athletes find that they can leg press staggeringly large loads on the leg press machine. I myself, having a lifetime PR squat of only 275 pounds, was able to leg press 540 pounds when I ran out of space to load more plates on the leg press machine. The discrepancy one's leg press and squat is twofold. First, the squat includes body weight. Second, the angle (Θ) of the leg press machine reduces the effective load by a factor of sin(Θ). Next time a w-pound person brags about their n-pound 45° leg press, they're really telling you about their n/√2 - w squat. Don't be like these people. Don't use the leg press machine at all. Just squat like a normal person.
The Smith machine is a squat rack with a bar fixed along rails. Some Smith machines have a system of pulleys to further control the bar. The Smith machine can be used for squats and bench presses. The Smith machine can be used safely without a spotter, which is nice, and the fixed bar path can allow athletes to move impressive weights. A typical athlete can squat considerably more in a Smith machine than they can with free weights. Moving more weight is not necessarily a good thing. Consider a typical athlete who can squat more while wearing a weightlifting belt than without. This tells us that the athlete's core leaks force. The Smith machine robs the athlete of much of the need to brace hard and transforms the exercise into pure force production. While this may hold some appeal, functional fitness training should prepare the body for real life situations and not theoretical maxes achieveable only through an artificial construct. Use a free barbell in a proper power rack instead of a Smith machine when possible.
The hamstring curl is a strange movement. Is there any sport that benefits from developing strength in this direction? I think not. This does not mean that hamstrings should be ignored. Rather, hamstrings should be trained systemically with the squat, lunge, deadlift, and hip thrust, but training this muscle in isolation is unnatural and unlikely to deliver any measurable benefit.
When I see someone deadlifting with knees locked out from the top I generally assume they simply don't know what they are doing — especially when the weight is small. Advanced athletes with a huge deadlift might benefit from this movement (under the supervision of a competent coach), but average athletes are much better off doing normal deadlifts.
Front and side raises are usually performed standing with small dumbbells. The elbow is kept locked as the weight is moved in the sagittal or coronal plane using the deltoids. Like the overhead arm clap, raises are very stressful to the deltoids and can be damaging to overall shoulder health. The standing overhead press is superior in every way. The press works the same muscles, and many more, with much less risk to shoulder health and in a functional movement pattern. No firefighter has ever handed a teammate a tool by hinging only at the shoulder. Even if one thinks of a bizarre situation where such a movement pattern does apply, we be prepare the body for such unknowable situations by training strengthening the entire body systemically.
The kettlebell swing can do miracles for an athlete's posterior chain — but only if performed correctly. The kettlebell swing is a hip hinge movement that builds strength, speed, and endurance. The kettlebell swing does not stress the deltoids at all. I see bad kettlebell swings from athletes at all fitness levels. A bad kettlebell swing is a nominal hip hinge and a front raise. A correct kettlebell swing from the hips drives the kettlebell into the air explosively. The hands, arms, and shoulders serve only a supportive role. You can tell if someone is telling this by the acceleration and deceleration of the kettlebell. The kettlebell should be launched with enough force that its momentum ends at eye level, and the athlete should be able to momentarily let go of the kettlebell at the top of the movement. By contrast, an athlete who front raises a kettlebell with their deltoids will find the kettlebell immediately plummets to the ground if they let go at the top because the kettlebell has no momentum as it is forced upwards throughout the movement. The kettlebell swing is a useful movement that requires a great deal of practice to master. Try to master the kettlebell swing.
For the same mechanical reasons, the American kettlebell swing (which raises the weight above the head) is a bad idea. The Russian kettlebell swing, where the weight only raises to eye-level, is a superior movement. One simply cannot generate enough momentum to bring a reasonably heavy kettlebell overhead without using the shoulder muscles.
A fitness program I participated in had this silly exercise where you held two small kettlebells, stood on one foot on a soft mat, and tried to perform a single-leg RDL. This might be a useful technique for physical therapists who offer rehabilitation, but it felt like a waste of time and energy to me. Use this exericse only as directed by a professional.
The front squat puts the bar in front of the athlete. The bar is primarily supported along the deltoids and is pressed into the clavicle. Athletes with good mobility should also support the bar with a few fingers, or even a full grip, with the arms rotated forward and palms facing skyward. Some athletes with poor mobility will cross their forearms and hold the bar with palms facing downward. This cross-armed grip is sometimes called the "California grip" and should be avoided. This grip causes the shoulders to rotate internally, compromising the stability of the upper back. If the upper back cannot do its job then the lower back has to compensate. The front squat should not, ordinarily, be stressful to the lower back. This force leak robs exercise of its effectiveness because the athlete will not attempt the heavy lifts that they should be capable of. An athlete who cannot assume a proper clean grip can progress to it using straps, or they can try the Zercher and Frankenstein squats. A Frankenstein squat is a front squat with arms fully extended in front of the body.
Novice lifters often complain that the back squat is uncomfortable for their necks. They need to deal with it and learn to squeeze their shoulder baldes into a "shelf" for the bar. A squat pad is a cylindrical cushion to make the bar more comfortable. This pad is counterproductive because it forces the shoulders to externally rotate more than they ordinarily should in the squat. Many novice lifters, and some gymbros, have trouble holding the bar and touch the plates instead. No human should have such poor shoulder mobility. You may be able to help the athlete's shoulders with shoulder dislocations using a stick or PVC pipe. Save your trainee's shoulders by refusing them squat pads.
The shoulders are too important to our lives and happiness to destroy with dangerous exercises. The squat pad only incidentally puts the shoulder into a precarious position; the behind-the-neck press and behind-the-neck pulldown actively put the shoulder into a dangerous position under load. These exercises have little carryover to functional activites one expects to see in sport and life. Avoid this position in favor of more comfortable and more powerful exercises in front of the body.
The box squat is a squat variation where the lifter puts a box behind them and touches it at the bottom of the lift. Many advanced powerlifters, notably Westside, use this method extensively. If you are an advanced powerlifter training for competition under a coach then go for it. If this is not you then I caution against this method for the sake of your spine. The purpose of the box squat is to pause at the bottom of the movement, eliminating any bounce and forcing the lifter to brace hard. The box squat is not a method to validate squat depth. Videorecord your lifts if depth is a concern.
As an aside on the box squat, if you absolutely must do the box squat, do so in a power rack. I watched two "gymbros" drop a barbell on a box, permanently bending the bar.
The lunge is a wonderful exercise. It stimulates hypertrophy, mobility, and balance. It will make you very sore at first but you can, and should, get used to them and work up to 400 meters at a time. You don't ever need to do any of your lunges with an external load for three reasons. First, the lunge is already stressful to the ankles, knees, and hips and adding weight adds risk. Second, the added risk is not worth it because whatever weight you add will be so small in relation to your squat that it isn't worthwhile. Lunges are not difficult because you aren't strong enough. Lunges are difficult because your legs don't stretch this far when you walk. Third, strength training is most effective when it employs the entire body at once as a system. There aren't many situations in life where we push with only one leg, but we can best prepare our legs for these unusual situations by maximizing strength using a proper squat. Everyone should lunge, but no one should lunge with an external load. (2019-09-02: I no longer think loaded lunges are a bad thing. Watch my video about doing a mile of lunges every week.)
Running is probably the most fundamental athletic skill shared by most sports. Running has many benefits to health and fitness and is likely the most popular exercise in the world. For all its popularity, running can be done wrong. Mammals, unlike birds, employ a discrete set of different gaits that change depending on pace. Birds look funny when they run because they move their legs the same way, just faster. Mammals don't do this. Running is a mechanically distinct activity from walking. Running itself can be divided into several gaits. Jogging is the slowest version. Think of a sports team team as they reset positions after a goal. Running is a bit faster than jogging and requires an longer stride and higher chest. Sprinting is the fastest human movement. A barefoot runner may find that they strike at the heel when jogging, midfoot when running, and forefoot when sprinting. Jogging is very stressful to the joints and produces a great deal of cortisol, which increases appetite and undermines testosterone production. Spending too much time in the "fat burn zone" signals to the body that it needs to store fat to meet this stimulus. Jogging is too light to stimulate strength gains. Endurance gains plateau very quickly as the body adapts to the demand. Contrast jogging to sprinting. The most advanced athletes in the world can only sustain a maximum effort sprint for a minute or so. Sprinting builds both strength and endurance, and does so in a fraction of the time. People around the world will casually waste millions of hours each day by jogging. These efforts yield a net loss. Long slow runs make long slow runners. Sprint instead.
If jogging is bad then loaded jogging is horrible. Popular loads include knapsacks and weighted vests. Some call this activity "ruck running." I think we should adopt a different name. How about "a feckless endeavor that does harm to the ankles, knees, hips, back, and shoulders, which also stimulates fat gains and does nothing to improve strength or speed?" A touch long, I admit. I'm sure you've heard the phrase "the sum is greater than the parts." With loaded logging, the sum is less than the parts. Loaded jogging teaches the body to run slowly; the athlete does not learn to sprint faster. Loaded jogging cannot be performed with a heavy weight; the athlete does not get stronger. One might argue that this activity is necessary in some endeavors, such as war and firefighting, and this is true. A 120 pound enlistee might be rightly concerned about the physical demands of patrolling with 60 pounds of equipment on their person. I recommend to this person they squat, every day, with a maximal load to stimulate muscle growth. Those 60 pounds of equipment won't be so bad once for someone who weighs 180 pounds. If loaded jogging was a good way to gain 60 pounds then bodybuilders would be doing it. They don't.
I can't say something bad about jogging without saying something horrible about speed walking. In short: never. Never speed walk. Just try. Try to keep up with your kid, who is on a bicycle, by speed walking. You will naturally break into a jogging gait. Speed walking (or "race walking") is unsafe, unnatural, and should have never been included as an Olympic sport.
Gyms are full of sophisticated machines that target individual muscles in isolation. Some gyms have a machine dedicated to hip abduction or adduction. The user sits in a chair and forces their legs open or closed against an adjustable resistance. It looks ridiculous. Perhaps people want to fill a "hip dip." Hip abduction and adduction simply isn't a movement that needs to be practiced. A wrestler or fighter might try to use this machine to improve their leg ride or guard, but they will probably develop more strength, endurance, and technique from sparring than these machines. Weak hip adduction is very apparent in novice athletes as they squat. If the knees trend inward as the athlete squats, this indicates weak hip adduction. The fix is not to target the hips with a special machine. The lifter just needs to consciously force the knees open as they squat. A few weeks practice will cure this problem forever. If the problem persists, squat with knees lightly banded. Lots of people go to gyms to look cool; the leg spreading machine is not cool.
If only gyms had staircases.
The battling ropes are a staple of HIIT. Hold the end of a heavy rope in each hand and swing them up out in opposite phases. The goal of this exercise is to maximally stimulate the heart, usually for just 20-30 seconds at a time. HIIT has a strong scientific basis and has become very popular. The problem with the battling ropes is that the activity is easy to cheat, difficult to measure, and fundamentally solo. Athletes should generally not perform this activity in a fatigued state; a tired body will not be able to move fast enough to bring the heart to its peak. If an athlete trains with the battling ropes each week for a year, can they objectively measure their progress? Not easily. Finally, a workout partner can easily "sandbag" the battling ropes and look like they're trying, but in a fair sprint we can easily tell who is still trying. The battling ropes is not inherently a bad exercise, people just need to perform it at maximal effort.
Once upon a time a famous boxer lost a match. He said that his opponent had a unique talent for punching slowly while applying force upwards instead of forwards. Just kidding, this never happened. Specificity is a principle of fitness training that teaches us that practice should be closely aligned to competition. Many athletes have experimented with training heavier, longer, and farther than they will in competition. For example, a baseball player might practice with a heavy bat. A wrestler might spar for three minute bouts instead of two. A runner might train for a three mile run, hoping that a two mile run will become easy. The baseball player may find that his timing and accuracy diminishes when he returns to a standard bat. Both the wrestler and the runner may tell you that "I didn't get tired, but I just couldn't push myself as hard as I needed to." While this article has primarily focused on achieving generic physical fitness adaptations, I certainly recommend athletes of one sport train to their sport. The sport of boxing is won with fast hands that apply force forward. The sport of boxing is not won with slow hands that apply force in the upward direction.
Would you allow a surgeon to operate but leave tidying up the messy bits afterward to the patient? Of course not. Why then do we allow bad coaches to leave recovery up to the trainee? Now, stretching falls in and out of vogue every few years. Stretching is not so important after weightlifting, a deep squat pulls on the achilles and hamstrings nicely, but stretching is very important after running, bicycling, and any activity that uses a short range of motion. When I was 25 I suffered from runners knee in both legs. I ran fast, but both knees hurt badly on each step and hurt most just after the workout. After several months I finally saw a doctor who showed me a "single leg over" stretch for the iliotibial (IT) band. My runner's knee went away within days. Several years later I participated in a fitness program that introduced me to resistance bands. We routed the bands over our shoulders, laid on our backs, and pulled on our feet. This stretch did miracles for my hamstring mobility. At age 30, I found that I could effortlessly bend down and touch my toes — something I could not do at age 15. Running is harmful to mobility. If you are a coach and you have an athlete run then you must lead them in stretching to prevent injuries.
The purpose of this exercise is unclear. Which muscles does it benefit? What sport does it prepare us for? How do we scale the activity for the beginners? How do we intensify it for the elite? The cynic in me believes this exercise is employed as a hazing tool by irresponsible coaches. The dreaded burpee is a superior exercise. Human arms are too short and too weak to walk like a quadruped.
Both the dangers and benefits of the sit-up are probably overstated. Many athletes express concern with any exercise that puts the spine into flexion or extension. I do not necessarily share these concerns. Your spine will flex when you pick up an awkward object, such as an atlas stone, and your spine will extend during intercourse. Sit-ups should, of course, be done only on a soft mat and never a hard floor. The real problem with the sit-up is that it is not a "core" exercise. The sit-up primarily uses the hip flexor muscle. What is a better core exercise? The crunch? The plank? No, the deadlift is a better core exercise. Direct abdominal work is a painful waste of time that could be better spent getting strong. If one insists on direct abdominal training, consider an ab wheel and Pallof press.
From a supine position, raise the feet and shoulders from the ground, hinging at the hip with knees slightly bent. Rotate in the transverse plane with the legs counterbalancing the arms. A variation of this exercise keeps the feet anchrored to the ground and adds a weight to the hands. This "core" bodybuilding exercise is intened to develop abdominal muscles. Unfortunately, all abdominal exercises can be foiled by a common problem: fat. The abdominal muscles themselves are small, thin, and easily hidden by adipose tissue. Common "core" exercises like the Russian twist, sit-up, plank, and crunches are generally too low in intensity to seriously increase the heart rate, which in turn implies they do little to burn fat. Furthermore, these exercises do little to build functional strength and endurance. Sure, an athlete might see modest improvements in their Russian twist in the first few weeks, but these results will quickly diminish and bring little benefit to sport. To reduce fat, sprint. To build a strong core, try the Turkish get-up.
The push-up might be the worst-performed exercise in the world, in both absolute numbers and as a percentage of attempts. The push-up requires no equipment, little coaching, and much more strength and discipline than people expect. Sport-specific rules will dictate what a "correct" push-up entails. Some organizations only require the humerus become parallel to the ground. Others require the chest to touch. Some people are picky about keeping the hips locked, others more lenient. A disappointing percentage of supposedly strong people, such as soldiers and policeman, cannot perform a single push-up with good technique, and only a small percentage of humans can do more than 50 push-ups with very strict form. A vanishingly small percentage of humans can do more than 100 push-ups well. When coaches demand their athletes perform vast numbers of push-ups, they implicitly accept poor performance. I reject this activity. Push-ups are a fantastic exercise, but they should only be practiced with full range-of-motion (ROM) and strict technique. If an athlete can only perform 20 push-ups well then they need to practice strict sets of 10. If an athlete cannot do one push-up then they should bench press, overhead press, and plank. Practicing partial ROM push-ups will make the athlete good at partial ROM push-ups and ingrain the movement pattern.
As a teenager my wrestling coaches had us practice for our two-minute sport with three-minute drills. Likewise, many athletes practice their sport for longer times or greater distances than is used in competition. This practice is common and sounds reasonable on the surface, but in fact it is less than optimal. Athletes need to practice the pacing of their sport. Consider two hypothetical runners, one who practiced for a two-mile competition by running two miles and the other three. The runner who practiced running two miles at a time may be better trained to optimally push their body without guesswork.
It should be pretty clear at this point that I believe in movements that are both compound and functional. You don't need much equipment; I recommend a barbell set, a tire, a couple kettlebells, a power rack with pull-up bar, and a bench. The staples of any serious fitness regime should be the squat, deadlift, press, bench press, sprint, and pull-up/chin-up. Two good fitness programs are Starting Strength and 5/3/1.
Good leg exercises include the high-bar back squat, low-bar back squat, front squat, overhead squat, goblet squat, hack squat, Zercher squat, lunge, and sled push.
Effective back exercises include the conventional deadlift, sumo deadlift, hex-bar ("trap-bar") deadlift, tire flip, clean, snatch, and Russian kettlebell swing.
Useful upper-body pushing exercises include the bench press, overhead press, dips, kettlebell clean and press, Turkish get up, burpee, and hand-release push-up.
Helpful upper-body pulling exercises include the farmer's walk, stone carry, pull-up, chin-up, sled drag, band pull-aparts, face pull, and row. Rowing includes rowing machines used for cardio, such as the Concept2 popularized by CrossFit.
All athletes should sprint regularly. Minimal running shoes, hills, and friendly competition will bring out the best in you.
Non-specialized athletes should supplement their training with hiking, rock climbing, and swimming. Casual sports, such as a round of Frisbee with the kids, are a great way to mix variety with fun. The occasional 5K in your community is good for you.
Sleep is critical for good health. The best way to know if you are getting enough sleep is to stop using an alarm clock. If you cannot make it to work/school in time without an alarm clock, then you need to go to be earlier. Ideally, you should sleep in a cool, completely dark, and completely quiet room that is dedicated to sleeping. Avoid looking at screens (TV/computer/phone) in the hour leading to bedtime. Abstain from caffeine for the six hours prior to bed. Understand that the sedative effects of alcohol actually harm sleep quality. A smart watch, such as a Fitbit, is useful to quantify and record sleep duration and quality.
If you want to lose weight I recommend intermittent fasting (20 hours fast, 4 hours eating, black coffee is OK). If you want to gain weight then I recommend drinking a gallon of whole milk each day.
Wear flip-flops in warm weather to strengthen your feet. Squat when using the toilet. You may find it useful to supplement your diet with creatine, fish oil, zinc, and vitamin D.