Athletes with chronically tight, uncomfortable calf muscles and Achilles tendons are often told to carry out passive, non-sports-specific stretches in an attempt to “unlock” their calves, ease the tightness, improve range of motion, reduce the risk of further injury, and ultimately boost athletic performance. For example, an athlete with bowstring-tight Achilles tendons might be advised to utilise a stretch in which the athlete stood about 12 inches from a wall, inclined his/her body forward toward the wall, and supported his/her body weight with hands on the wall, inducing a mild stretch in both Achilles. Alternatively, the Achilles and calf muscles might be stretched out manually by grasping the foot and forcing the ankle(s) through dorsiflexion. The athlete might even – while in a seated position on the floor with legs outstretched – place a rolled-up towel over the bottom of the affected foot and pull the foot toward the shin, lengthening the calf muscles and Achilles tendon in the process.
While such stretching seems to ease calf and Achilles tendon tightness, at least anecdotally, doubts have been expressed as to whether such non-dynamic stretches really produce greater range of motion and lower levels of calf tightness during sporting activity. To see whether static stretching has a significant impact on dynamic range of motion, researchers at Emory University in Atlanta, Georgia, recently worked with 24 individuals (21 women and three men) with a history of lower-extremity overuse injury and limited ankle-joint dorsiflexion. A control group participated in a three-week, static, calf-muscle-and-Achilles-tendon stretching programme, while a control group received no intervention. Static, passive dorsiflexion was measured with a standard goniometer (“Plantarflexor Stretching Effects on Static and Dynamic Ankle Dorsiflexion,” Journal of Orthopaedic and Sports Physical Therapy, Vol. 32(1), p. A-5 (PL12), 2002).
The stretching programme did improve static dorsiflexion (essentially, the ability to move the ankle joint in such a way that the top of the foot moved closer to the shin, without accompanying body movement), but dynamic dorsiflexion (similar movement of the ankle but while the subjects were actually walking) was not improved at all by the stretching regime. As the researchers rightly concluded, “Plantarflexor muscle stretching programmes prescribed to increase static ankle dorsiflexion may not alter ankle joint kinematics during ambulation.”
Why is this so?
There is no problem explaining the Emory findings. After all, there is this small thing called the nervous system which controls all muscular activity. To put it simply, if the nervous system is not taught to upgrade dynamic flexibility, it will not produce improved dynamic flexibility, even if static flexibility is greatly attenuated. If an athlete wants better flexibility during motion, especially during the motions associated with his/her sport, he/she had better use stretches which replicate some of the dynamic movements of the sport. As an example, athletes with significant calf-muscle and Achilles-tendon tightness would be far better off using the following stretching routine, rather than static manoeuvres for their calves: balance and eccentric reaches with toes (for improved, dynamic Achilles-tendon and calf-muscle flexibility): To carry out this exercise correctly, start by standing on only your right foot as you face a wall, with your right foot about 30 inches or so from the wall (you may need to adjust this distance slightly). Your left foot should be off the ground and positioned toward the front of your body, with your left leg relatively straight. Then, bend your right leg at the knee while maintaining your upper body in a relatively vertical position and nearly directly over your right foot. As you bend your right leg, move your left toes toward the wall until they touch, keeping the left leg relatively straight. End the movement by returning to the starting position. Then, conduct essentially the same motion, but move your left foot forward and to the left, again keeping your left leg straight and attempting to make contact with the wall and letting body weight shift to the medial side of your right foot. Your left foot may not quite reach the wall, since you are moving in a frontal plane (from right to left) in addition to the straight-ahead, sagittal plane. Return to the starting position, and then carry out essentially the same motion, but with your left foot crossing over the front of your body and going to the right as you attempt to touch the wall; let your body weight shift to the lateral part of your right foot as you do this. Then return to the starting position, and you have completed one rep on your right foot. Start with two sets of eight reps per foot.
Rehabilitation programmes following ACL reconstruction typically concentrate on strengthening the quadriceps’ musculature. But should physios and strength and conditioning coaches be looking at other muscles a little lower down that may also need some rehabilitation? Michael Ross is the chief of physical therapy at Cannon Air Force Base and he suggests the calf muscles are often overlooked in many ACL rehab programmes. What’s the problem? Research shows that calf muscle weakness does exist following ACL reconstruction. Various methods of assessment have been used to determine the level of deficit, ranging from sophisticated isokinetic measurements to simple functional tests such as heel raises. The results were always the same, reduced strength, suggesting rehab programmes should address calf-muscle weakness. Bearing in mind the important part these muscles play during most sporting activities, Michael Ross (Strength and Conditioning Journal, Vol 4 Number 1, pp 71-72) has come up with an effective alternative to more traditional strengthening exercises such as the seated or standing calf extension. Ross believes that this exercise places the muscles in a more functional position ensuring that the calf is strengthened in manner specific to its function during gait.
To perform the exercise you will need to stand about one arm’s length away from a wall. Take a short step backward. There should be a slight forward lean to the body as you support yourself against the wall. Stand on the leg you want to work. Flex your knee approximately 30-40 degrees, return to a position where the knee is straight, and then plantar flex the ankle. To increase the intensity of the exercise you can hold a set of dumbbells, but remember the calf muscles are slow-twitch endurance muscles that help stabilise the lower leg during gait, so keep the reps high and the resistance low if you want to get the maximum benefit from your rehab programme.
Electromyographic comparison of standard and modified closed chain isometric knee extension exercises. What side of the fence would you sit on if you were asked which type of exercise provided the most benefit during rehabilitation and conditioning: open or closed kinetic chain? During the past decade there has been a movement toward the increased use of closed kinetic-chain exercises due to the ability of the athlete to perform functional exercises. Closed kinetic-chain exercises are generally defined as weight-bearing activities involving more than one joint with the distal end of the extremity fixed (e.g. squat). Conversely, open kinetic-chain exercises are typically non-weight- bearing, isolate a single joint, and allow movement at the distal end of the extremity (e.g. knee extensions). It could be argued that both forms of exercise have their place in rehabilitation training programmes.
Currently, no apparatus exists to provide the benefits of both open and closed chain knee extension exercises. But what if an exercise existed that brought together the best of both worlds? That is exactly what a research team based in Kentucky have been attempting to produce and they may have cracked it (Journal of Strength and Conditioning Research, Vol 16 (1), pp 129-134). The research team modified a conventional isokinetic machine by placing a footplate to the resistance arm of the machine so that axial loading occurs at the foot and shank as subjects perform an isometric knee extension. In doing so, the research team created an environment that provided the benefits of both open and closed kinetic-chain exercises. The next stage was to put the modified machine through its paces using 15 female volunteers. The subjects performed maximal volitional isometric contractions under two conditions. The open-chain condition required subjects to perform a knee extension by pushing directly into the tibial pad of the apparatus in an attempt to extend the knee. In the second condition the subjects performed a knee extension using the modified apparatus. During this condition there was no contact between the tibia and the resistance arm; subjects pushed maximally down into the footplate while attempting to perform a knee extension. EMG activity during each condition was recorded from the following muscles: vastus medialis obliquus; mid-belly of the rectus femoris; mid-belly of medial and lateral hamstrings; medial and lateral heads of the gastrocnemius, tenor fascia lata and gluteus maximus.
So what was the outcome once all the data had been collected and the numbers crunched? The team found significant differences existed in EMG activity between each condition. The vastus medialis (36%), medial (23%) and lateral (36.3%) hamstrings, medial (31%) and lateral (33%) gastrocnemius were all more active during the modified closed kinetic-chain knee extension as compared to the traditional open kinetic-chain exercise. In contrast, the rectus femoris muscle displayed greater activation during the open kinetic-chain exercise. Although this is the first study of its type, the Kentucky-based research team are confident they have found an exercise that may provide the best of both worlds. The modifications may provide a valuable exercise intervention that combines the relative quadriceps femoris isolation of the traditional seated knee extension with the co-activation of dynamic knee-stabilising synergist benefits provided by squat-type movements. The modification also decreases anterior knee shear forces, thereby providing patients rehabbing from ACL injuries or reconstruction a safer environment to train in. It may not be long before you see this type of equipment turning up in your local gym. Until then, however, you will have to continue using the more traditional approaches currently on offer, which brings us back to where we started – which side of the fence do you sit on?
Repeated eccentric exercise bouts do not exacerbate muscle damage Delayed onset muscular soreness (DOMS) can quite literally be a real pain in the bum! DOMS often occurs after a tough resistance training session, due in part to the increased amount of eccentric work your muscles are expected to cope with throughout the session. Traditional thinking suggests that it is harmful for injured soft tissues to receive a damaging stimulus (training session) during the early stages of the recovery process. Professional and recreational athletes alike are reluctant to take days out from their training regime due to an attack of the DOMS and often attempt to train through the pain. In doing so, it is generally thought that they could well be causing further damage to their soft tissues. Clearly this makes life difficult for many athletes. The burning question is, should they train through the pain at the risk of further injury or take some time out from training and hope their fitness levels don’t drop off?
Recently, some of the guesswork was removed by a piece of collaborative research carried out in Japan and Western Australia (Journal of Strength and Conditioning Research, Volume 16 (1), pp 117-122). The study examined whether performing repeated bouts of eccentric exercise two and four days after an initial damaging bout of exercise would result in an increase in muscle damage. Subjects completed three sets of 10 repetitions of eccentric actions of the elbow flexors using a dumbbell. One arm performed a single bout of this exercise and then two weeks later the other arm performed the identical exercise followed by the same bout two and four days after the first. The study showed that no significant changes in indicators of muscle damage were observed when the exercise bouts were repeated compared to a single bout of exercise. There were no significant differences in changes in maximal isometric force, range of movement, muscle soreness or plasma CPK levels (blood borne indicator of muscles damage) between the two exercise conditions. The multinational research team concludes that when training with sore muscles, no additional damaged is induced and recovery is not affected by the additional training sessions. This is clearly good news for athletes who don’t want to take a couple of days off from training because they are suffering from DOMS.