Are you hitting the gym or doing cardio regularly but not seeing improvements in athletic performance or body composition? Or perhaps you are already working with a personal trainer in Mississauga and the same thing is happening. It’s very common to hit a plateau and get complacent doing the same fitness routine but this will not yield results because of a principle known as progressive overload. Progressive overload is the gradual increase of stress placed upon the body during exercise training. It states that in order for any of the 5 components of fitness (muscular strength, endurance, cardiovascular fitness, body composition and flexibility) to improve, increasingly greater demands must be placed on the body during exercise training. To state it very simply: no pain, no gain! Progressive overload can be manipulated through a number of different variables such as load, speed, range of motion, training volume, time under tension, rest periods, training frequency and exercise selection. Load, speed, range of motion, training volume and exercise selection produce structural adaptations in the form of hypertrophy (muscle growth) and increase the body’s ability to recruit more muscle (muscle strength). Time under tension and rest periods produce metabolic adaptations in the form of increasing energy stores, cardiovascular capacity and muscular endurance which influences how much work you can accomplish during an exercise session and how fast you can recover between exercises.
The simplest way of implementing progressive overload is to keep increasing the load of any resistance exercise over a period of time. Increasing the load will recruit and damage more muscles fibers providing a stimulus for strength and hypertrophy. It is easy to increase the load when using weights or any other form of external resistance but more complicated when bodyweight resistance is involved. In case of bodyweight resistance the load can be increased by applying additional external resistance in the form of a weight vest or changing the torque around a joint by altering biomechanics (for example, doing decline pushups or close grip pushups applies more resistance to certain muscles). A third way is to introduce an element of instability (for example doing pushups on a medicine ball).
The speed at which resistance is overcome determines what muscle fibers are stimulated and the degree of muscle fiber recruitment. Overcoming resistance faster stimulates type II muscles fibers to work thus providing a stimulus for hypertrophy. Exercises done in an explosive manner like plyometric box jumps, clapping pushups, resisted punching and sprinting will accomplish this.
Time Under Tension
Time under tension is the total duration of time that muscles stay contracted during any given exercise. Varying the time under tension (TUT) produces a number of effects. Increasing the total time under tension for each exercise during a workout will burn more calories due to increased oxygen uptake as well as the EPOC effect. Increasing the TUT will produce metabolic adaptations such as increases in muscle glycogen, creatine phosphate and ATP as well as cardio vascular adaptations such as reduced body fat, increased VO2 max, increased respiratory capacity, increased mitochondrial and capillary densities and improved enzyme activity. These metabolic adaptations lead to increased muscular endurance, and an increased aerobic and cardiovascular capacity. Increasing TUT also provides a stimulus for muscles to grow via a mechanism called sacroplasmic hypertrophy where the muscle gets bigger due to an increase in the amount of energy stores in the sarcoplasm which is the area outside the muscle fibers. Time under tension can be easily controlled for any exercise by doing more reps per set, introducing static holds or isometric contractions and varying the tempo at which the exercise is performed.
Range of Motion
Range of motion (ROM) affects which muscles work during an exercise– making it an important factor in developing functional strength and in determining the appearance of a person’s physique. Functional strength can be defined as having sufficient strength to overcome resistance at any point in the ROM. ROM is especially relevant when doing compound exercises (exercises that involve more than 1 join and multiple muscle groups) because different muscles take over at a certain ROM (i.e., for a pushup the chest is more active at the bottom end of ROM and the triceps take over in the mid range). Performing an exercise with full ROM has been shown to yield significantly greater improvements in muscle thickness and strength compared to performing the same exercise with limited ROM. However, reducing ROM can be effective for targeting and strengthening specific muscles and can be used to improve a weak point during an exercise. Therefore increasing, as well as reducing ROM can provide an overload stimulus, but the goal must be considered. For example additional ROM can be introduced when doing pushups by using pushup bars and going lower into the ROM to target the chest; static holds can be done at the bottom of the range to target the chest even more.
Rest periods produce adaptations in the cardiovascular system and affect which energy systems are active. Decreasing the duration of rest periods between sets increases the demand for oxygen producing cardiovascular adaptations and increasing aerobic capacity. Shorter rest periods have also been shown to increase the release more growth hormone. At moderate loads and short rest periods the body cannot supply oxygen at the required rate to provide energy to muscles so the anaerobic energy system has to kick in and supply additional energy. A consequence of this is the production of lactic acid and this happens when you are out of breath during a workout and start getting cramps. Training this way (moderate loads and short rest periods) will allow your body to get rid of the lactic acid faster and will extend the time before you start getting cramps. This will allow you to exercise at a higher level of intensity for a longer duration of time
Training volume is traditionally defined as the number of reps multiplied by the number of sets multiplied by the weight (volume = reps x sets x weight). Volume is proportional to the total amount of work done (work = mass x distance) in the training session. The more weight you move (whether it’s bodyweight or external resistance) over a longer distance (sets x reps) the more work you accomplish. Increasing volume over time in a training program accomplishes several things. Doing more work burns more calories per workout resulting in more fat loss. High volume workouts provide a stimulus for hypertrophy through a number of mechanisms (myofibril hypertrophy, sacroplasmic hypertrophy, and release of growth hormone). Volume is inversely proportional to load, and recovery. You cannot continuously train at high volume with heavy loads without compromising recovery. Doing so could potentially lead to overtraining, decreased performance and injury.
Exercise selection determines which muscles are worked and how a person’s physique will look as it develops. Compound exercises work many muscle groups resulting in greater energy expenditure, which is good for developing functional strength and for fat loss. Isolation exercises target specific muscles. Targeting specific muscles is desirable in cases where there is a muscle imbalance and certain muscles must be strengthened –such as when a person is recovering from an injury and needs to target and strengthen specific muscles– or for aesthetic purposes -such as when a bodybuilder wants bigger biceps. Generally a training program should mostly consist of compound exercises and isolation exercises should be added where required. The overload principle can be applied to exercise selection in several ways. Compound exercises can be made more challenging by altering form and the position of limbs to increase torque around a joint and to target specific muscle groups (for example doing close grip pushups increases torque in the elbow and makes the triceps work more). Bodyweight exercises can be made more challenging by introducing more difficult variations of the same exercise. For example someone who lacks the strength to do flat pushups should start with incline pushups and gradually reduce the level of incline as they get stronger.
You can manipulate any of these variables to improve your fitness level but it’s best to focus on one at a time if you are just starting out. The most common method is to keep increasing the load for any given exercise over time. Which variables you choose to manipulate ultimately depends on your fitness goals. For example, if you want to build muscle and get stronger then you can increase the load, speed, range of motion and volume. If you want to lose weight, improve your cardio vascular fitness and increase your work and recovery capacity then you can increase the time under tension, increase the volume or decrease the rest periods.