What athletes should do when their quadriceps muscles start going downhill
Twenty-four hours after your first major football (or cricket, rugby, basketball, etc.) competition of the season, your leg muscles are so sore that even easy jogging produces considerable discomfort, and it is impossible to carry out the training you have planned for the day. The biggest moaners in your legs are your quadriceps femoris muscles (the 'quads') in your thighs; they cry out in pain each time one of your feet hits the ground as you jog along slowly. What can be done to prevent such muscle carnage, particularly with regard to those complaining quads?
The answer, of course, is to let your quads go downhill. No - we don't mean you should allow your quads to become weaker; we want you to expose your quads to some downhill running. A judicious amount of well-timed downhill running can actually help prevent leg-muscle soreness, especially in your quadriceps muscles.
If this seems a little bizarre, remember that muscle soreness often results when one's muscles are challenged by a greater-than-normal number of 'eccentric actions', in which the muscles attempt to shorten while they are actually being elongated. The quads are notorious soreheads, mainly because gravity pulls the knee downward (eg, produces knee flexion) with every footstrike during the act of running. This gravity- and impact-induced flexing at the knee stretches out the quads at the exact time they are attempting to shorten to prevent excessive knee flexion. The resulting, repetitive, high-tension strain (which occurs about 90 times per minute per leg as you run) can produce significant quadriceps-muscle damage.
Normal training for your sport, of course, protects your quads to some extent; the quads simply get used to a certain level of eccentric action. However, if you run more than you usually do because you are involved in a major match or serious preparatory workout, your quads won't be fully prepared to handle the extra stress. If you run faster than you usually do, your quads will also be prone to trouble; increased limb acceleration heightens impact forces in the leg and forces the quads to work harder (and more quickly) to control knee flexion.
'Downhill running gives this adaptation a special boost, so that it will be hard to damage your quads, even when you go beyond your usual training limits'
Even when you are not running faster than usual, downhill running magnifies the eccentric, 'pulling-apart' stress on the quads, because the leg 'falls' a little farther than normal with each stride. Thus the acceleration of the leg is greater at impact (footstrike), and the forces which produce knee flexion are consequently higher. The quads, of course, still attempt to carry out their yeoman-like work of resisting knee flexion, but the stress on them is much higher. Microscopic tears in the quads' muscle fibres and connective tissues can occur, and considerable soreness can result.
That makes downhill running sound a bad idea, but in fact the small-scale controlled damage associated with well-regulated downhill efforts actually forces your quads to adapt and strengthen themselves so that they will be more immune to damage during subsequent challenges. Think back to the first serious workouts you ever carried out in your sport, for example. Your muscles were undoubtedly sore the following day, and perhaps they were painful for several weeks whenever you undertook particularly challenging training sessions. Gradually, however, you developed the capacity to work at high levels without incurring much soreness; your muscles had adapted to the strain produced during your training. Downhill running gives this adaptation process a special boost, so that it will be hard to damage your quads - even when you go beyond your usual training limits.
If you carry out your downhill runs properly, your quads will be only slightly sore after the first negative-incline session, and after a few bouts of downhill effort it will be hard to get your quads to react negatively to even the most heated football contest, the most-prolonged, multi-set tennis match, or a much-longer-than-usual run. Supplying protection for your quads is easy and straightforward, and the protection applies to everything that you do - not just to future downhill running.
The six-week factor
Amazingly enough, just one downhill workout can furnish decent protection for the quads, and the 'soreness insurance' provided by a single bout of downhill running can in some cases last for six weeks or more. Several years ago, scientists at the University of Massachusetts asked 109 individuals to perform two sets of 35 maximal, eccentric contractions of the biceps muscle in the upper part of one arm. Basically, these eccentric contractions consisted of lowering a very heavy weight, which forced the biceps muscles to elongate as the weight was lowered; simultaneously, biceps-muscle fibres were attempting to shorten to stabilise the weight's movement.
After this unusual workout, biceps soreness and tightness peaked about two to three days later, and maximal swelling occurred a few days after that. Biceps strength declined immediately after the rigorous session and stayed below-par for 10 days.
The biceps muscles were clearly damaged by the eccentric workout (we won't hurt your legs to this extent with our recommended downhill sessions below, because we don't want you to lose 10 good days of training), but they adapted very nicely. When the individuals tried the same biceps routine six weeks later, there was appreciably less soreness and little loss of muscle strength, even though there had been no intervening biceps training. The biceps muscles were somehow protected from problems as a result of that initial eccentric session.
Why pain after 10 weeks?
Interestingly enough, the protection didn't last much longer than six weeks. When a second group of subjects waited 10 weeks after their initial eccentric workout to stress their biceps again, their biceps were thrown into uncontrollable agony and lost most of their strength. What was going on? Why could the biceps 'remember' what happened six weeks before - but not 10 weeks before?
The Massachusetts researchers speculated that a strenuous bout of eccentric exercise 'teaches' the nervous system how to better control and distribute the forces that are acting on particular muscles. In theory, this lessens the strain on individual muscle fibres when eccentric activity tries to tear them apart and thereby reduces muscle damage and consequent pain. Just as the nervous system can learn to do this, it can also forget, and this forgetting seems to take place after slightly more than six weeks (bear in mind that the rate of forgetting may depend on the severity of the initial workout; a 'timid' eccentric workout might be forgotten after four weeks, while a strongly fibre-damaging one could be retained by the nervous system for a couple of months).
Australian rats reveal sarcomere secrets
The Massachusetts neural theory is a nice one, but does it really work that way? To check it out, scientists at Monash University in Australia tested 16 laboratory rats on treadmills over a five-day period. Eight of these rats participated only in 'uphill' (inclined) running, while the other eight ran only 'downhill' (declined running). Actual workouts consisted of five-minute work intervals with 1.5-minute recoveries, starting with three work intervals on the first day of training and building up to seven intervals on the fifth day. Running speed during the work intervals was a rather modest 16 metres per minute (yes, that's a 100-minute mile, but remember that rats have short legs). After five days, the rats' quadriceps muscles were tested for strength and then biopsied.
A key finding was that the quadriceps muscle cells of the decline-trained rats contained almost 10% more sarcomeres per cell, compared to the quads of the inclined rodents. To understand what sarcomeres are, bear in mind that a muscle cell is a barrel-shaped structure, and each 'barrel' is filled with several hundred to several thousand cylindrical, threadlike structures called myofibrils. To picture this, simply imagine a pipe-shaped structure (the muscle cell) stuffed with countless numbers of small cylindrical wires (the myofibrils). Incidentally, when we say that a muscle cell is shaped like a pipe, we are referring to a section of cylindrical water pipe, not to a pipe used for smoking purposes.
The myofibrils themselves are composed of microscopic, cylindrical compartments laid end to end (picture tiny cylinders or cotton reels glued together at their ends to make one long cylinder). These compartments are called the sarcomeres, and within the sarcomeres are the proteins (filaments) which actually allow muscles to both shorten and elongate. As special filaments slide inward (toward the middles of the sarcomeres), the myofibrils and overall muscle cell shorten, but when the filaments slide outward, the muscle gets longer.
As mentioned, downhill running induced the muscle cells to add more sarcomeres to their myofibrils. Why is this increase in number of sarcomeres beneficial, and how can it prevent muscle damage and soreness? Since muscle-cell length itself didn't change significantly as a result of the downhill running, the fact that there were more sarcomeres per muscle cell meant that during eccentric contractions, when the whole muscle cell was elongating, each sarcomere in a downhill-trained muscle would have to elongate less, and thus each sarcomere would be less likely to sustain internal damage.
More sarcomeres mean less strain
To illustrate this point, let's say that there are two muscle cells which are each one-inch long but must stretch out to two inches during an eccentric action. If one of these muscle cells has 10 sarcomeres, but the other (the downhill-trained fibre) has 20, you can easily see that the 10 sarcomeres would each have to stretch out by one-tenth of an inch to get the cell up to two inches, but the 20 sarcomeres in the other cell would only have to stretch by one-twentieth of an inch each to make the cell long enough. There is less strain on the sarcomeres during an eccentric contraction when there are more sarcomeres per myofibril. It's a pretty neat adaptation!
Thus, when you run downhill, you're giving your muscle cells a wake-up call to start tacking on more sarcomeres. The increased sarcomere density then reduces stress on the myofibrils and protects you against soreness and damage accruing from future downhill running and very tough or prolonged workouts and races (if the Massachusetts neural theory is also correct, your nervous system also helps out by distributing strain more effectively and evenly throughout your muscles). Since damage is lessened, it also means that you can recover more quickly from very severe training sessions and competitions - and be ready for subsequent quality work more quickly than the poor oik with fewer sarcomeres.
The up-and-down Kenyans
It's no accident that élite Kenyan runners train unceasingly on uphills and downhills and can carry out more quality training than any other runners in the world without being debilitated by muscular soreness and stiffness (five-time world cross-country champion Paul Tergat is rumoured to carry out five to six red-hot sessions per week when he is training seriously, and Kenyan runners participating in the pre-World-Championship Kenyan national cross-country camp routinely conduct six sizzling sessions per week and 19 weekly workouts overall). Schooled on the severe inclines in the western part of the Rift Valley (or on the Aberdares' harsh slopes if the runner happens to come from central Kenya), the Kenyans' muscles probably possess a surfeit of sarcomeres and thus are more resistant to the wear-and-tear damage associated with both very fast and very high-volume running.
One shouldn't forget, too, that the presence of more sarcomeres means that muscle contractions can take place more quickly, since each sarcomere has to shorten less to make the overall muscle cell compress (the sliding of the filaments over one another inside sarcomeres takes time; the further they have to slide, the longer it takes to condense a muscle). Using our example of one-inch muscle cells again, but this time saying that they must contract to a length of one-half inch, one can readily see that the 10-sarcomere cell must shorten by .05 inches per sarcomere, while the 20-sarcomere fibre needs to abbreviate by just .025 inches per sarcomere. The combination of quick-contracting, injury-resistant muscles is a trademark of the Kenyan runners.
Here's what to do
So how should you actually carry out your protective, downhill workouts? Once a week for about four weeks, go to a hill which slopes downward for 50 metres or more; for your initial workout, choose a hill with a very modest declination of about 3 to 4% or so; you can increase the severity of the grade later, after you have become a seasoned downhill runner. After a good warm-up, begin carrying out 'reps' which consist of nothing more than running down your chosen slope. At first, don't attempt to run rapidly; simply use a customary training pace. Each time you get to the bottom of the hill, turn around, jog back to the top (the ascents are not noted for their soreness-reducing properties, but they are nicely strengthening for all the muscles in your legs), and continue. For your first downhill effort, maintain this pattern for 10 minutes, giving you slightly less than five total minutes of downhill running (ascents usually take longer than descents).
'You may also choose to upgrade the speed of your downhill running, within reason, and you may want to begin utilising a steeper hill'
Your quads' behaviour during the 48 hours after this initial session will provide you with much information about their eccentric strength and soreness-resistance. If they flare up with considerable pain and stiffness during this follow-up period, you can derive some measure of comfort from ibuprofen or some similar non-steroidal anti-inflammatory medication - and from knowing that your quads really needed this training and will truly be stronger in the future (once healing has occurred). Your next workout - carried out after about a week - should be exactly the same as the first, and you will notice considerably less quad complaining after this one. Like the athletes who experienced no troubles after the initial, 10-minute downhill trial, you will then begin to gradually increase the amount of time you spend on the hill. Expanding the total hill running in three- to five-minute increments per session works well for many athletes. For example, you might choose to progress from 10 total minutes of running (including downhill and uphill) to 14 minutes for the next workout. If there are no serious problems, you could move to 18 minutes for the subsequent session, and so on. You may also choose to upgrade the speed of your downhill running, within reason, and you may want to begin utilising a steeper hill (avoid severely steep slopes which dramatically change your running biomechanics, however). You may continue this overall progression for longer than four weeks, if you like, but a four-week programme (with one hill workout each week) should fortify your quads against unusual pain for at least six weeks after the fourth workout - and probably longer.
Things to watch for
A few 'form pointers' may help you with your hill workouts. As you run down your chosen slope, lean forward naturally and comfortably; avoid the temptation to lean back with your upper body. Don't let yourself get out of control, but don't stiffen up or resist the hill too much; learn to stay coordinated and balanced as gravity does much of the work for you.
Recent research indicates that you can manipulate your stride lengths slightly to reduce the soreness associated with your initial stab at downhill training but that you will eventually have to 'pay' your soreness bill unless you continue to understride on hills. In an investigation carried out at the School of Sport, Health, and Exercise Sciences at the University of Wales in Bangor, 18 male runners (average age 21 years) ran downhill using their preferred stride lengths, extra-long stride lengths (overstrides), or abbreviated strides (understrides). Two weeks later, the runners ran downhill again, this time using their preferred stride lengths. Muscle strength and soreness were assessed after each bout of running ('Effect of Stride Length Manipulation on Symptoms of Exercise-Induced Muscle Damage and the Repeated Bout Effect,' Journal of Sports Science, Vol. 19(5), pp. 333-340, 2001).
After the first downhill exertion, the overstride group suffered from the most soreness, while the understride group retained the most strength. This makes sense: during overstriding on downslopes, a foot falls farther with each step and is thus travelling at a higher speed when it hits the running surface (remember that gravity accelerates motion). As a result, impact forces are greater, and the quads must undergo augmented strain to control flexion at the knee. In contrast, understriding reduces foot speed at impact and lowers the strain on the quads. In effect, the understriders had less damage after the first workout, compared with the normal striders and overstriders, but would they also have as much protection from soreness and muscle-strength loss during subsequent efforts?
No! After the second bout of downhill running, which occurred two weeks after the first, the initial understriders retained strength just as well as the normal striders and overstriders, indicating that the initial, pain-reducing understriding did not interfere with the quads' ability to maintain usual strength levels after eccentric exercise. However, the initial understriders were least protected from soreness associated with the second bout of running; they had to pay their pain bill as soon as they began to run normally! For this reason, we recommend simply using your normal strides as you run downhill; don't try to consciously minimise stride length as part of an effort to control soreness. Control post-exercise pain by utilising reasonable, non-excessive workouts, not with running-form adjustments.
Protecting the hamstrings and...
This training protocol will do a great job of shielding your quads from soreness and injury, but what about the muscles running along the backs of your legs, especially your hamstrings and calf muscles? Jogging or walking backwards down hills has sometimes been recommended as a way of fortifying those muscles. Although such a strategy makes a certain amount of sense, the gains in pain resistance will probably not be as great as those attained for the quads, unless you plan to carry out future workouts and competitions while running backwards. Remember that there is probably a neural component to pain protection; your nervous system learns and remembers patterns of muscular control which control damage and pain. While your nervous system is a great thing, it may not be able to apply the lessons it incorporates from backwards movement to straight-ahead running, since the two patterns of locomotion are so different.
Perhaps the best way to protect your hamstrings from pain is to carry out high-bench step-ups with regularity. To do these, begin from a standing position on top of a knee-high bench or step, with your full body weight supported by your left foot. Your right foot should be free and held slightly behind your body. Lower your body in a controlled manner (in effect doing a one-leg 'squat' with your left leg) until the toes of your right foot touch the ground, while continuing to support all of your weight on your left foot. Return to the starting position by applying force to the bench or step with your left foot and by straightening your left leg. Repeat for a total of 10 reps, and then switch over to the right leg. It is critical that you maintain absolutely upright posture with your trunk throughout this entire movement; avoid the tendency to lean forward for balance as your 'trailing' leg drops toward the floor.
This exercise places incredible eccentric stress on the hamstrings, so it should be approached cautiously, especially if you have had hamstring troubles in the past. Begin with just 10 reps per leg, and gradually increase to three sets of 20 reps. As your strength and skill improve, you may also hold dumbbells while you carry out the exercise. Another advanced form of this exercise works as follows: As your trailing, non-weight-bearing leg ascends after touching the floor, accelerate its movement, flex the knee, and bring the thigh of this leg out in front of your body, so that the thigh is actually parallel with the bench surface. As you do so, swing the opposite arm forward, too. In effect, you are mimicking an aggressive running stride. Hold the thigh parallel with the bench for a moment, continuing to support full body weight on one leg, and then gradually drop the leg behind you again as you squat with the support leg. This is a great exercise for building hamstring strength and overall balance!
...the calf muscles
To improve eccentric strength of your calf muscles, simply carry out single-leg heel raises on an inclined surface. To do these, stand with relaxed, erect posture on a slightly inclined surface (a pavement on a moderate hill will work, in case you don't have a special inclined board), with all your body weight supported on your right foot and your right knee barely flexed (your left leg should be flexed at the knee so that your left foot is off the ground and your left shin is roughly parallel with the floor). Contract your right calf muscles as strongly as possible, so that your right heel rises vertically off the ground and you rock forward on your foot, supporting full body weight on your toes and extreme forefoot. That's the beginning position for your one-footed heel raises.
Now, let your right heel move back toward the ground smoothly, evenly, and swiftly. Don't collapse your ankle, don't let your foot wobble from side to side, and don't let your upper body jerk around - just drop your heel toward the ground quickly and efficiently. As you do this, body-weight support will shift from your toes and forefoot to the mid-foot region.
As your right heel initiates contact with the ground, let your right ankle dorsiflex naturally, and let your right knee increase its flexion (obviously, your ankle and knee will be flexing simultaneously). As you do all this, your right hip will be in a slightly flexed position. Let the ankle and knee flex slightly more than they would during the stance phase of your gait cycle when you are running. All of this should be done with control and quickness.
Once you have achieved ankle and knee flexion, don't dally - immediately rock back up onto your toes, plantar-flexing your right ankle at the same time as you are straightening out your right knee. Hold this position for two seconds - and you have completed one rep!
In your first stab at this exercise, continue on for about 10 to 15 more reps on your right foot, and then give your other calf a chance to join in the fun, completing an identical number of reps on your left side. As you perform the exercise, move rhythmically and without any hesitation in the overall movement (except for the two-second 'holds' on tiptoe), and try to maintain good balance, posture, and stability at all times (initially, you may grab a wall, fence, or other structure for support if you are having trouble with your balance). Attempt to maintain a running-specific posture at all times, and try to sustain a 'feeling of rhythmic, relaxed running' as you rock back and forth on your foot; don't scrunch up your upper body, and don't look down at your legs as you carry out the movements.
So what's the bottom line? When you carry out your pain-preventing downhill training, it's nice to remember that your uphill climbs are enhancing your economy, and your downhill runs are having a profound impact on your leg-muscles' eccentric strength and ability to stand up to hard training. By running downhill, you are adding sarcomeres to your leg-muscle cells, and those additional sarcomeres should quicken your strides and help keep you free from injury and soreness in the future. In addition, carrying out high-bench step-ups and one-leg heel raises on an inclined surface will protect the 'back' sides of your legs. The freedom from injury which you attain will allow you to train and compete more consistently and thus become a much better athlete.