Resistance Training’s Effect on Endurance Performance

Research shows that the appropriate integration of resistance training into the endurance athlete’s training can result in significantly better performance when compared to classic endurance training plans that focus only on aerobic endurance.

The following is an exclusive excerpt from the book Developing Speed, part of the NSCA’s Science of Strength and Conditioning Series with Human Kinetics.

Endurance athletes who are stronger can generally perform at a much higher level.

This suggests that training modalities that stimulate increases in muscular strength without compromising endurance capacity may be beneficial for the endurance athlete. Support for this contention can be found in the scientific literature; research shows that the appropriate integration of resistance training into the endurance athlete’s training plan can result in significantly better performance when compared to classic endurance training plans that focus only on aerobic endurance training.

When looking closely at endurance performance, several key factors—including the athlete’s maximal aerobic power (V˙ O2max), lactate threshold, and movement efficiency—contribute to performance (see figure 7.1). The training modality selected influences these factors by inducing changes to the athlete’s aerobic power and capacity, anaerobic capabilities, and neuromuscular function.

Aerobic training exerts a strong influence on both aerobic power and capacity, but it does not exert a great impact on the athlete’s anaerobic or neuromuscular abilities.

Conversely, resistance training exerts a strong influence on the athlete’s neuromuscular function and a moderate influence on anaerobic power and capacity, while offering only a minimal influence on aerobic power and capacity. By influencing the athlete’s anaerobic abilities as well as neuromuscular function, resistance training can elevate the athlete’s lactate threshold, movement efficiency, and ability to engage in high-intensity activities.

The ability of resistance training to improve endurance performance is likely related to several key factors, including the specific physiological and mechanical adaptations that are stimulated by the resistance training regimen. The integration of resistance training into the overall training plan appears to be central to creating these specific performance-enhancing adaptations.

Traditionally, endurance athletes and coaches have believed that resistance training either does not affect or negatively affects endurance performance. However, this view may be partially explained by a design flaw in many of the training programs that include both resistance and endurance training. The flaw is that resistance training is simply added to the endurance training plan. Athletes who undertake this approach often experience excessively high levels of fatigue that can negatively affect overall performance.

If athletes reduce their endurance training load to account for the addition of resistance training, then resistance training has a positive effect on the athletes’ endurance performance. The athlete who performs both resistance and endurance training in an integrated and appropriately planned fashion will perform at a higher level than the athlete who performs only classic endurance training.

Understanding Methylation

Methylation is a key biochemical process that is essential for the proper function of almost all of your body’s systems. It occurs billions of times every second; it helps repair your DNA on a daily basis; it controls homocysteine (an unhealthy compound that can damage blood vessels); it helps recycle molecules needed for detoxification; and it helps maintain mood and keep inflammation in check.

To keep methylation running smoothly you need optimal levels of B vitamins. Without enough B vitamins methylation breaks down, and the results can be catastrophic. In these cases we see more birth defects like spina bifida, more cases of Down’s syndrome, and more miscarriage.

A breakdown in methylation also puts you at higher risk for conditions like osteoporosis, diabetes, cervical dysplasia and cancer, colon cancer, lung cancer, depression, pediatric cognitive dysfunction ( mood and other behavioral disorders), dementia, stroke and may put you at a higher risk of heart disease.

To avoid all of these problems, the key is to maximize methylation. That means avoiding the things that cause your methylation to break down, testing to find out how well your methylation is working, and including the things that support proper methylation. Let’s look at how to do that.

8 Factors that Affect Your Methylation Process

1. Genetics – Like an estimated 20 percent of us, you could be genetically predisposed to high homocysteine
2. Poor diet – The word “folate” comes from “foliage.” You need to eat plenty of leafy greens, beans, fruit, and whole grains to get adequate levels of vitamins B6 and B12, betaine, and folate. Egg yolks, meat, liver, and oily fish are the main dietary sources of vitamin B12 — so long-term vegan diets can be a problem. Plus, certain compounds can raise levels of homocysteine and deplete the B vitamins. These include excess animal protein, sugar, saturated fat, coffee, and alcohol. Irradiation of food depletes nutrients, so foods treated this way may be lower in B vitamins, too
3. Smoking – The carbon monoxide from cigarette smoke inactivates vitamin B6
4. Malabsorption – Conditions like digestive diseases, food allergies, and even aging can reduce absorption of nutrients
5. Decreased stomach acid – Aging and other conditions can reduce stomach acid — and therefore absorption of vitamin B12
6. Medications – Drugs like acid blockers, methotrexate (for cancer and arthritis and other autoimmune diseases), oral contraceptives, HCTZ (for high blood pressure), and Dilantin (for seizures) can all affect levels of B vitamins
7. Other conditions – These include hypothyroidism, kidney failure or having only one kidney, cancer, and pregnancy
8. Toxic exposures – Some toxins can interfere with vitamin production

Watch out for these factors and you will go a long way toward protecting your methylation.

Measuring Your Own Methylation Process

To find out if your methylation process is optimal, ask your doctor for the following tests:

• Complete blood count – Large red blood cells or anemia can be a sign of poor methylation. Red blood cells with a mean corpuscular volume (MCV) greater than 95 can signal a methylation problem
• Homocysteine – This is one of the most important tests you can ask for. The normal level is less than 13, but the ideal level is likely between 6 and 8
• Serum or urinary methylmalonic acid – This is a more specific test for vitamin B12 insufficiency. Your levels may be elevated even if you have a normal serum vitamin B12 or homocysteine level
• Specific urinary amino acids – These can be used to look for unusual metabolism disorders involving vitamins B6 or B12 or folate, which may not show up just by checking methylmalonic acid or homocysteine

12 Tips to Optimize Your Methylation Process

Just as there are many causes of poor methylation, there are lots of things that support its proper functioning. Here’s how to maximize methylation — and prevent conditions like heart disease, cancer, dementia, depression, and more.

1. Eat more dark, leafy greens – You want to eat l cup a day of vegetables like bok choy, escarole, Swiss chard, kale, watercress, spinach, or dandelion, mustard, collard, or beet greens. These are among the most abundant sources of the nutrients needed for optimal methylation
2. Get more Bs in your diet – Good food sources include sunflower seeds and wheat germ (vitamin B6); fish and eggs (vitamin B6 and B12); cheese (B12); beans and walnuts (vitamin B6 and folate); leafy dark green vegetables; asparagus, almonds, and whole grains (folate); and liver (all three)
3. Minimize poor quality animal protein, sugar, and saturated fat – Animal protein directly increases homocysteine. Sugar and saturated fat deplete your body’s vitamin stores
4. Avoid processed foods and canned foods – These are depleted in vitamins
5. Avoid caffeine – Excess amounts can deplete your B vitamin levels
6. Limit alcohol to 3 drinks a week – More than this can deplete your B vitamin levels
7. Don’t smoke – As noted above, smoking inactivates vitamin B6
8. Avoid medications that interfere with methylation – See notes on this above
9. Keep the bacteria in your gut healthy – Take probiotic supplements and use other measures to make sure the bacteria in your gut are healthy so you can properly absorb the vitamins you do get
10. Improve stomach acid – Use herbal digestives (bitters) or taking supplemental HCl
11. Take supplements that prevent damage from homocysteine –Antioxidants protect you from homocysteine damage. Also make sure you support methylation with supplements like magnesium and zinc
12. Supplement to help support proper homocysteine metabolism – Talk to your doctor to determine the best doses and forms for you.  Here are a few suggestions:
    Folate (folic acid): Amounts can vary based on individual needs from 200 mcg to 1 mg. Some people may also need to take preformed folate (folinic acid or 5 formylTHF) to bypass some of the steps in activating folic acid
    Vitamin B6: Take 2 to 5 mg a day. Some people may need up to 250 mg or even special “active” B6 (pyridoxyl-5-phosphate) to achieve the greatest effect. Doses higher than 500 mg may cause nerve injury
    Vitamin B12: Doses of 500 mcg may be needed to protect against heart disease. Oral vitamin B12 isn’t well absorbed; you may need up to 1 or 2 mg daily. Ask your doctor about B12 shots
    Betaine: This amino acid derivative is needed in doses from 500 to 3,000 mg a day, depending on the person

Understanding Cholesterol

Cholesterol is one of the least understood molecules and truly gets a "bad rap." Although people understand that cholesterol is only present in animal-based foods, what many do not know is that we produce cholesterol just like any other animal, and it is a very necessary molecule used to form all of the cell membranes in the body. Cholesterol is also the building-block molecule from which all of the steroid hormones are made. If there is more cholesterol in the diet than is needed, then the body synthesizes less. If the diet does not provide enough cholesterol then the body makes more.

Since cholesterol is used by the body to manufacture hormones such as cortisol, we can look at what cortisol is and make some logical connections. Cortisol is widely regarded as a "stress hormone" since the body needs and produces more of it in response to stress. This stress response takes many forms; one of them is lowering inflammation--useful if your version of stress involves hand-to-hand combat with large carnivores or fighting for your life. The lowering of inflammation is why the pharmaceutical versions of cortisol (Hydrocortizone and other glucocorticoids) are used to reduce inflammation in cases of massive trauma or major surgery. Other effects of cortisol are the elevation of blood pressure, release of glucose from the liver, inhibition of the immune system, retaining of water/reducing kidney function (probably useful if the combat with the large carnivores leads to bleeding form flesh wounds, as retaining water would help to maintain blood volume when bleeding profusely) and other effects. Taken together, when stress levels remain high, lots of cortisol is produced. It would then make sense that making a lot of cortisol requires a lot of what is made from, which is cholesterol. Therefor, during periods of high stress (a lifetime for many people), the levels of cholesterol can become very elevated. When the stress is long-term, the stress will end up raising the inflammation level through other mechanisms; effectively, stress reduces inflammation in the short-term only. Cholesterol has many other uses in the body, including the formation of myelin--the insulating/speeding sheath that wraps around the nerves, like rubber coating surrounding a copper wire, that increases their conduction velocity (and is damaged in multiple sclerosis).

Dietary modifications to reduce cholesterol has been met with mixed results. Some people can follow a strict no-cholesterol diet and achieve a lowering of their plasma cholesterol levels, while other are not able to accomplish this. This failure of dietary regimen to achieve the desired goal may be because of the body's production of cholesterol to meet the necessary levels for the amount of stress the individual is experiencing. The failure may also be because of reduced utilization of cholesterol. The gut bacteria play a role here also with Lactobacillus bacteria actively consuming cholesterol. Lactobacillus not only consumes cholesterol, but it makes bile acids that aid in the digestion of fats out of the cholesterol that it consumes. It therefore makes sense that if a person has altered gut bacteria demographies and Lactobacillus are in the minority, that person will not use up as much cholesterol and the cholesterol levels may accumulate. Elevated levels of stress reduce the levels of Lactobacillus, providing the pathway for stress to reduce the beneficial effects of a healthy diet. The same imbalance may also predispose the person to inflammation, which is the real cause of heart disease.

The use of probiotics in dairy products to control cholesterol greatly predates modern science, as the Maasai tribe in Kenya use a probiotic fermented milk in their diet. The Maasai diet is composed almost entirely of meat, milk and blood. This diet includes several times the recommended level of cholesterol, and yet the Maasai have no problems with atherosclerosis or other degenerative diseases that could be related to their diet. What has been found is that their fermented milk (no refrigeration, so it all gets fermented if not immediately consumed!) contains probiotic bacterial population s that help to consume and lower cholesterol. Other sources of probiotics, such as yogurt, have been found to lower cholesterol levels also. 

Many people incorporate yogurt into their diet because they like it or they think that it is healthy--but what makes it healthy? Much of the yogurt on store shelves has no bacterial colony whatsoever, so it is important to read the ingredients! If it has no "live active cultures," then it has little if any health benefit to our good bacteria and subsequent immune function.

Eggs have often been the poster child of high cholesterol food, if the yolk is used. However, consuming eggs may not have as much to do with elevated cholesterol level as initially thought. Similarly, fats were implicated in the disease process, as it has been observed that people with high triglycerides (fats) in their blood are at increased risk of developing heart disease. There are other variables in this equation, as is often the case. For example, abnormal populations of gut bacteria promote atherosclerosis by causing inflammatory changes and altered metabolism of lipids. The presence of abnormal gut bacteria that cause irritable bowel syndrome is directly linked to the development of thickening of the wall of arteries, which is of course the actual structural change that is at the center of what we call atherosclerosis.

Excerpt from The Symboint Factor by Richard Matthews DC DACNB FACFN

Healthcare: Treating the Symptoms and Not the Problem

We experience symptoms of illness (ie high blood pressure or dysbiosis)  as a sign that something within the body is not working as it should. The presence of symptoms should alert a person that the body has become imbalanced in some way, so that action can be taken to restore balance and function. Instead, most people are taught to treat the symptoms only. Examples would be taking pain relievers to control pain or using muscle relaxers for muscle spasms or even blood pressure pills and statin drugs to help with risk factors for heart disease. This unfortunately does not correct the underlying imbalance that caused the dysfunction and symptom to result. The true problem may continue creating imbalances in the body's system until more serious conditions manifest. 

There are few cases of "one cause, one cure" that happen in the human body. Pursuing health means maximizing the function of all the body's intrinsic systems as well as the brain. This is a completely different concept than what we usually encounter in healthcare. Often asked is the question: "will my insurance cover that?" when explaining health-building strategies, and the answer is almost always a "no." The reason is that insurance companies sell disease care policies, not health care policies. The number of pure health building interventions that are covered, if any, can often be counted on one hand. For example, does insurance cover nutritional supplements, gym memberships, yoga classes, new bicycles, probiotic foods, kitchen tools such as a VitaMix and similar items? Perhaps some of these are covered items in some countries, but not in the United States. Nothing that prevents cancer is covered, but annual early detection is, to see if your have it yet. The "system" is geared toward specific treatment for a specific disease, and yet almost all diseases have several factors or circumstances as causes. If a person falls and breaks a wrist, the doctor that treats that wrist has a very specific job. If the patient instead has arthritis and migraines, what are the causes? Inflammation, poor diet, biomechanical issues, lifestyle, genetics--four out of five of these are variables that we have control over and yet often do nothing about.

Adapted from The Symboint Factor by Richard Matthews DC DACNB FACFN

Avoid the Worst Ingredients

Flavor enhancers, preservatives, sweeteners, synthetic colors and manmade fats and chemicals commonly hide out in the ultra-processed foods we eat. If you want to stay away from putting harmful chemicals on your table, it’s necessary to learn how to identify the worst ingredients and find healthier alternatives. Let’s take a look at how to get started.

1. Identify and avoid these seriously dangerous additives

It’s not easy to remember all of the worst ingredients to steer clear of, but learning to avoid the most toxic ones commonly found in the food supply can drastically improve your health. A common food additive is monosodium glutamate (MSG) that is very dangerous and affects human body in a variety of ways. Headache, nausea, vomiting, pain in the back of the neck, numbness and heart palpitations are common side-effects of consuming MSG. Monosodium glutamate is an excitotoxin that overexcites the cells in your body to the extent where they are so heavily damaged that they die. MSG also leads to a range of neurological diseases on prolonged exposure. (1, 2)

It’s not easy to find processed foods that are completely free of MSG. Other food ingredients often mask the presence of MSG, including:

• autolyzed yeast
• hydrolyzed protein
• hydrolyzed vegetable protein
• sodium caseinate
• yeast nutrient or yeast extract
• Torulo yeast
• natural flavoring
• glutamic acid

Soy sauce, seasonings, powdered milk, stock, malt, maltodextrin, pectin and anything protein often contain MSG.

2. Avoid the toxic heart attack ingredient

Trans fats are very harmful. These artificial trans fatty acids lower the level of good cholesterol (HDL) and increase the level of bad cholesterol (LDL) in your body. Primarily used in processed foods, trans fats are formed when food manufacturers add hydrogen to liquid oil to solidify it. (They do this to increase shelf life.) Unfortunately, trans fats have been blamed for up to 50,000 premature heart attack deaths a year. (3)

In the hydrogenation process, oil is heated to an extremely high temperature of about 500 to 1000 degree Celsius. Hydrogenated oil is a fabulous preservative because all the natural enzymes are destroyed by the high heat, rendering the end product as an unhealthy sludge. If you see terms like hydrogenated oil, partially hydrogenated oil or fractionated oil on food label, do not buy the products.

3. Steer clear of metabolism-sinking sweeteners

Artificial sweeteners may seem like a good choice if you’re watching your calories, but science shows us it’s really one of the worst ingredients when it comes to your metabolic health. High-fructose corn syrup (HFCS) is a sweetener that leads to weight gain, heart complications and obesity.

Some artificial sweeteners result in headaches and mood swings as well. Aspartame, saccharin and sucralose are widely used artificial sweeteners and can exert a bigger load on your metabolic system than plain old sugar. They also trick your brain into feeling less full, prompting you to eat more, which in turn can lead to weight gain. So monitor your intake of artificial sweeteners to stay fit.

4. Beware of these 3-letter cancer causers

Butylated hydroxyanisole (BHA) and Butylated hydroxytoluene (BHT) are processed food preservatives that have been found to have carcinogenic properties by the International Agency for Research on Cancer. BHA has been declared safe by FDA, but it is termed ‘reasonably anticipated to be a human carcinogen’ by U.S. Department of Health and Human Services. (4, 5)

BHA has been shown to act as an endocrine disruptors, interfering with healthy hormone production, too. (6) BHA and BHT preservatives are commonly found in cereals, potato chips, chewing gum and cereal snack mixes. (Read your cosmetics labels, too. They often hide out in personal care products.)

5. Don’t assume soy is safer

Is soy bad for you? In the majority of cases, particularly as it pertains to soy as an ingredient in processed foods, it is unhealthy. While many of us think that soy and soy products as healthy and protein-rich, this is not always true. A majority of soy used in processed food products is genetically engineered. That means the crop has been tinkered with on a genetic level to receive applications of glyphosate, the main ingredient in Roundup weedkiller, without killing the plant. This has led to “excessive” levels of glyphosate turning up in the food we eat. (7) In 2015, the World Health Organization declared glyphosate “probably carcinogen to humans.” That makes conventional soy one of the worst ingredients.

Consuming GMO ingredients in considerable quantity over a long period of time is suspected to lead to infertility, gluten disorders, allergies and even cancer. Though the jury is still out on this controversial topic, with several studies showing that GMO ingredients are safe, I suggest practicing the precautionary principle, meaning it’s always best to consume processed foods that rely the least on GMO ingredients, staying as natural as possible. (8)

Factors in Non-Contact ACL Injuries

A short animation of typical conditions leading to a non-contact ACL injury.

Pre Workout Supplements: Hypertrophy Priority

Here are some supplement recommendations for athletes seeking to maximize Hypertrophy. With Hypertrophy we are trying to maximize the acidic environment to induce as much damage, cell swelling and hyperemia as possible. What can we take preworkout to help this along?

Primarily, we will want to look at things that shuttle nutrients and blood into the muscle. 

1. Citruline Malate: reduces fatigue and improves muscle endurance. More effective than Arginine. Arginine actually decreases GH during your workout when taken pre exercise. Arginine is best used before bed. 
2. Antioxidants : Alpha Lipoic Acid, grape seed extract and CoQ10 improve mitochondrial function and will allow for more blood flow to muscles during training.
3. Beet Root Powder: Vasodilator, will induce a pretty gnarly pump.
4. Neurotransmitter boosters: these will be important for anyone that has a hard time getting amped up to train. I advise against taking caffeine as a pre workout before Hypertrophy sessions because caffeine is a vaso constrictor. That means that taking caffeine with nutrients to chase the pump is a bit futile. There is a trade off for sure. If training without caffeine leads to a shit workout, then it may be worth your while to take caffeine instead of some of the vasodilators. Taking both at the same time though, to me, is a waste of money.
5. BCAAs: provides energy and will prevent muscle protein breakdown during training.
6. Creatine: will help sustain energy levels throughout your sessions and get more fluid into the muscles.

Why do partial squats not transfer very well to sport?

By Chris Beardsley, S&C Research columnist

Partial squats make you stronger at partial squats, but do not transfer to full squats. On the other hand, full squats make you stronger at full squats and also make you stronger at partial squats (although usually not quite as well as partial squats).

This is probably because the mechanisms that produce joint angle-specific strength gains are different after training at long muscle lengths, compared to training at short muscle lengths. Training at longer muscle lengths involves more regional hypertrophy, which seems to transfer better to strength across the whole range of motion.

Even so, many coaches have noted that the joint angles in partial squats are similar to the joint angles in the stance phase of running gait, or during jumping. Because of this similarity between joint angles, they suggest that partial squats should transfer better to sport than full squats, as they should produce the greatest gains in strength exactly where we need them.

And this makes a lot of sense.

On the other hand, most research shows that full squats are superior compared to partial squats for improving athletic performance in many respects, particularly jumping.

So what mechanism could be causing this disparity?

What is the background?

You should be able to follow this article without too many problems if you remember that we are normally stronger at one joint angle compared to all the rest, which we call the angle of peak torque.

This angle of peak torque can be changed in different ways, by different types of training.

Training programs using full ranges of motion, using long muscle lengths, or eccentrically all tend to move the angle of peak torque to a joint angle corresponding to a longer muscle-tendon length. In contrast, training programs using a partial range of motion, or short muscle lengths, tend to move the angle of peak torque to a joint angle corresponding to a shorter muscle-tendon length.

And most importantly, changing the angle of peak torque is very likely one of the main mechanisms that causes joint angle-specific gains in strength.

However, angles of peak torque are normally measured using isometric tests, and they might differ during dynamic contractions, particularly at higher speeds.

So does this happen?

Do angles of peak torque differ with angular velocity?

Full range of motion exercises might transfer better to sport than partial range of motion exercises if the angles of peak torque are different when we measure them at different speeds.

This will be particularly relevant if our exercises are traditional, heavy squats, as they involve much slower movement speeds than jumping or sprinting.

And this does happen!

The angle of peak torque is seen at joint angles corresponding to shorter muscle-tendon lengths as angular velocity increases (Moffroid et al. 1969; Knapik et al. 1983; Kannus & Jarvinen, 1991; Yoon et al. 1991; Khalaf et al. 1997; Khalaf et al. 2001; Khalaf & Parnianpour, 2001; Anderson et al. 2007; Ripamonti et al. 2008), although this effect is not always observed consistently in every study, and is much less marked above 180 degrees/s (Frey-Law et al. 2012).

The following charts derived from data reported by Yoon et al. (1991) show how the angle of peak torque alters with increasing angular velocity. Each line represents a different angular velocity moving through the same joint angle range of motion.

Here is knee flexion (contracting from left to right):

As you can see, as the movement speed increases, two things happen.

Firstly, the lines shift downwards, because force reduces as angular velocity increases (because of the force-velocity relationship).

Secondly, the angle of peak torque moves further to the right as angular velocity increases. This means that the angle of peak torque occurs at progressively shorter and shorter muscle-tendon lengths as angular velocity increases.

Here is knee extension (contracting from left to right):

Why do angles of peak torque differ with changing speed?

As you can see from the charts, the angle of peak torque moves to a joint angle that corresponds to shorter and shorter muscle-tendon lengths, with increasing speed.

This probably happens because even though the muscle-tendon lengths are the same at each joint angle, the muscle and tendon do not change length in the same way at different contraction speeds (don’t forget that tendons always lengthen to a greater or lesser extent when a muscle contracts, even when the contraction is purely a concentric contraction that involves a shortening of the muscle-tendon unit).

Fast contractions involve small muscle forces, which cause a smaller amount of tendon elongation at the start of the contraction.

The smaller amount of tendon elongation in fast contractions means that the muscle stays lengthened for longer in the concentric phase of the contraction. This allows the muscle to stay on the plateau of the length-tension curve for longer. Therefore, the angle of peak torque is shifted to much later in the overall joint angle range of motion (Murray et al. 1980).

Slow contractions involve high muscle forces, which cause much more tendon elongation at the start of the contraction.

This greater tendon elongation means that the muscle does not remain lengthened for very long during the concentric contraction. So it drops off the plateau of the length-tension curve quickly. Therefore, the angle of peak torque is seen earlier on in the overall joint angle range of motion (Murray et al. 1980). And isometric contractions are the slowest, strongest contractions of all.

Why is this important?

Why is contraction speed important for the angle of peak torque?

There are two key implications.

Firstly, it means that the angle of peak torque in dynamic movements is always at joint angles corresponding to shorter muscle-tendon lengths compared to the isometric angle of peak torque.

Secondly, it means that sporting movements at very high angular velocities have angles of peak torque at joint angles corresponding to very short muscle-tendon lengths. However, even when measured in the same person, these are not the same angles of peak torque as slower, barbell exercises or isometric tests. Those angles of peak torque occur at much longer muscle-tendon lengths.

This may be why full range of motion heavy resistance training exercises transfer better than similarly-loaded partial range of motion exercises to many high-velocity athletic movements.

What does this mean for jumping?

The quadriceps are key for jumping, and most jumping requires an angle of peak torque at moderate quadriceps lengths, as neither jumpers nor team sports athletes bend their knees down to the levels seen during a full squat before take-off.

This has led some coaches to assume that partial squats might be helpful, as they seem to involve a peak contraction around the same sort of joint angle.

But although this sounds logical, it ignores how the angle of peak torque changes with movement speed.

During a slow, heavy squat, the angle of peak torque will be observed at long muscle lengths. On the other hand, a jump is clearly a very fast movement and so the corresponding angle of peak torque will be at a much shorter muscle length.

If we train at long quadriceps muscle lengths, such as in the deep squat, we shift the angle of peak torque towards a longer muscle length. Because increasing movement speed moves angles of peak torques towards shorter muscle lengths, however, this will correspond to an angle of peak torque at moderate muscle lengths when we measure it at a fast velocity.

This is exactly where we need them for the jump.

If we train at short-to-moderate quadriceps muscle lengths, such as in the partial squat, we shift the angle of peak torque towards a shorter muscle length. Because increasing movement speed moves angles of peak torques towards shorter muscle lengths, however, this will correspond to an angle of peak torque at very short muscle lengths when we measure it at a fast velocity.

This is not where we want them for the jump.

And this is why deep squats transfer much better to jumping than partial squats (Weiss et al. 2000; Hartmann et al. 2012; Bloomquist et al. 2013).

Although there is less research available for sprinting, the same principles will apply.

Conclusions

Some people have proposed that partial squats should transfer better to sport than full squats because of the similar joint angles involved. However, full squats are definitely superior, and this is very clear in relation to jumping.

The reason for this discrepancy is that the angle of peak torque changes with movement speed. The angle of peak torque is found at shorter muscle-tendon lengths when measured at fast speeds, compared to when measured at slow speeds.

This is likely because even though the muscle-tendon lengths are the same at each joint angle, the muscle and tendon do not lengthen to the same extent at different speeds, and the amount of tendon elongation is less during fast contractions, which allows the muscle to remain on its length-tension plateau for longer.

Heavy, slow exercises such as full squats produce peak contractions at long muscle-tendon lengths. Because of differences in the amount that the tendon changes length, these angles of peak torque correspond very well to the peak contractions in athletic movements at joint angles corresponding to shorter muscle-tendon lengths, such as in jumping.

References

1. Anderson, D. E., Madigan, M. L., & Nussbaum, M. A. (2007). Maximum voluntary joint torque as a function of joint angle and angular velocity: model development and application to the lower limb.Journal of Biomechanics, 40(14), 3105-3113.
2. Bloomquist, K., Langberg, H., Karlsen, S., Madsgaard, S., Boesen, M., & Raastad, T. (2013). Effect of range of motion in heavy load squatting on muscle and tendon adaptations. European Journal of Applied Physiology, 113(8), 2133-2142.
3. Frey-Law, L. A., Laake, A., Avin, K. G., Heitsman, J., Marler, T., & Abdel-Malek, K. (2012). Knee and elbow 3d strength surfaces: peak torque-angle-velocity relationships. Journal of Applied Biomechanics, 28(6), 726-737.
4. Hartmann, H., Wirth, K., Klusemann, M., Dalic, J., Matuschek, C., & Schmidtbleicher, D. (2012). Influence of squatting depth on jumping performance. Journal of Strength & Conditioning Research, 26(12), 3243.
5. Kannus, P., & Jarvinen, M. (1991). Knee Angles of Isokinetic Peak Torques in Normal and Unstable Knee Joints. Isokinetics and Exercise Science, 1(2), 92-98.
6. Khalaf, K. A., Parnianpour, M., Sparto, P. J., & Simon, S. R. (1997). Modeling of functional trunk muscle performance: Interfacing ergonomics and spine rehabilitation in response to the ADA.Journal of Rehabilitation Research and Development, 34(4), 459.
7. Khalaf, K. A., Parnianpour, M., & Karakostas, T. (2001). Three dimensional surface representation of knee and hip joint torque capability. Biomedical Engineering: Applications, Basis and Communications, 13(02), 53-65.
8. Khalaf, K. A., & Parnianpour, M. (2001). A normative database of isokinetic upper-extremity joint strengths: towards the evaluation of dynamic human performance. Biomedical Engineering: Applications, Basis and Communications, 13(02), 79-92.
9. Knapik, J. J., Wright, J. E., Mawdsley, R. H., & Braun, J. (1983). Isometric, isotonic, and isokinetic torque variations in four muscle groups through a range of joint motion. Physical Therapy, 63(6), 938-947.
10. Moffroid, M., Whipple, R., Hofkosh, J., Lowman, E., & Thistle, H. (1969). A study of isokinetic exercise. Physical Therapy, 49(7), 735.
11. Murray, M. P., Gardner, G. M., Mollinger, L. A., & Sepic, S. B. (1980). Strength of Isometric and isokinetic contractions knee muscles of men aged 20 to 86. Physical Therapy, 60(4), 412-419.
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