Assistance Exercises for the Clean
The clean is an exercise that is fundamental to Olympic lifting as it is part of the clean and jerk which is one of the two contested lifts. The clean, and its variations, is also fundamental to many athletic strength and conditioning programs as it must be performed quickly, involves the barbell moving at a high velocity, is done standing, uses most of the muscles of the body, and requires the athlete to generate great levels of power to perform successfully.
This post is going to cover the following assistance exercises for the clean:
- Power Cleans
- Clean Pulls
- Front Squats
- Lifts from the Hang or Blocks
Power Cleans:
The power clean is the same exercise as the clean with a few important exceptions. First, the barbell is received in a quarter squat (as opposed to the full squat during the clean). Second, because the barbell is received higher, it must be pulled to a great height. So instead of pulling it to chest (and even diaphragm) level, it must be pulled to shoulder lever before dropping under the bar. Third, because the barbell is pulled to a greater height less weight can be handled, but more power must be generated. Finally, this exercise is easier to learn/perform because it does not require the same level of technique as the full clean.
This exercise helps to develop power and it also helps to condition lifters to pull the barbell higher. When helping to train the full clean, power cleans are generally done for three to five sets with one to six repetitions per set. It’s not unusual for a good lifter to be able to power clean 90% of what they can do in the full clean. They can be done after cleans in a workout or instead of full cleans.
Clean Pulls:
Clean pulls are a partial movement. The lifter performs the clean, but never gets under the barbell (i.e. the clean pull ends after the second pull of the clean). This allows for more weight to be handled, trains the explosive part of the lift, and helps to strengthen different phases of the lift.
Clean pulls are done for sets of three to six repetitions, usually with 5-10% more weight than the clean. Too much weight can be problematic because it may result in unintended consequences (learning poor technique like rounding the shoulders, performing the lift too slowly, or performing the lift in parts instead of smoothly). This means that caution needs to be exercised with clean pulls.
There are three types of clean pulls. The first is the clean pull, which is performed as described above. The second is the clean high pull. As the lifter goes into the explosive second pull, he/she pulls on the barbell with their arms raising it to chest/shoulder height. The third is the clean pull with no explosion, which involves performing a clean pull until the barbell reaches mid-thigh (i.e. it is essentially a deadlift with a clean grip).
Front Squats:
Front squats help to strengthen a lifter to be able to both support and stand up with weight during the clean. To perform front squats, the barbell begins on the front of the shoulders just as if it had been cleaned. Staying upright, the lifter squats down and then stands back up with the barbell on the front of the shoulders.
This is a strengthening exercise. It is also one that requires a great deal of technique and is not tolerant of mistakes. Normally this is done for no more than six repetitions per set.
Lifts from the Hang or from Blocks:
Cleans, power cleans, and clean pulls done from the hang (or from blocks) involve a starting position that is not the floor. This allows for weak phases of the lift to be developed. Lifts from the hang have the benefit of being nearly identical to the full lift and require the athlete to develop a stronger back and grip. However, the grip can be a limiting factor in being able to overload with lifts from the hang. This is solved by performing the lifts from raised blocks, but the danger is that the technique (and positions) don’t always resemble those seen in the actual lift. This means that there may be limited transfer or the development of bad habits.
To see examples some of the exercises described, see: http://youtu.be/a4ScAP3gbSA , http://youtu.be/5HN2Df168KU, and http://youtu.be/9CTzTh3ZHew.
The table below shows a sample week that utilizes the above exercises to help train the clean.
| Monday | Tuesday | Wednesday | Thursday | Friday | Saturday |
| Clean, hang, AK, 5x3x80%
Clean Pull + Power Clean, 3×6+3×70% Split Jerks, 5x3x80% Front Squats, 5x4x80% |
Snatch workout | Clean + Jerk, 5×3+2×70%
Clean Pull, hang, AK, 3x3x75% RDL’s, 3×6 Good Mornings, Standing, 3×8 |
Snatch workout | General strength training | Clean + Front Squat + Jerk, 3×3+6+2×70%
Snatch workout |
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The Hamstrings and Sprinting
Schache et al, published in the April issue of Medicine and Science in Sports and Exercise, conducted a study investigating how each of the three hamstring muscles experience sprinting. The authors studied seven sprinters (five males and two females) who were sprinting at an average of 8.95 meters/second in the study (this equates to 11.17 second 100 meter sprint). The athletes were studied running 80 meters of a 110 meter indoor track in terms of kinematics and kinetics. The authors studied the following muscles: semimembranosus, semitendinosus, biceps femoris long head, biceps femoris short head.
Basically the sprinting motion can be broken into the following phases:
- Foot off
- Swing
- Foot strike
- Stance
The results are interesting and suggest that the muscles have a slightly different function during the sprinting motion:
- All the muscles studied achieved peak length and generated peak force prior to footstrike (roughly from 50 to 75% of the stride cycle). The exception is the force production of the short head of the biceps femoris which has two peaks, one prior to foot strike and one after.
- All the muscles achieved their maximum shortness right after the foot off phase (during the first 25% of the stride cycle).
- All the muscles generate their maximum power prior to footstrike, but this is preceded by an absorbing phase.
Regarding some of the musculoskeletal measures:
- The long head of the biceps femoris achieves peak strain, peak lengthening velocity, and peak force during the swing phase slightly earlier in the sprinting cycle than the other hamstring muscles.
- The short head of the biceps femoris achieves peak strain, peak force during the swing phase, and peak power absorption later than all the other hamstring muscles. It also generates peak power earlier in the stride cycle than the other hamstring muscles.
Of the hamstring muscles:
- The long head of the biceps femoris experiences the greatest strain during the sprinting motion.
- The semitendinosus has the greatest shortening velocity and the greatest lengthening velocity during the sprinting motion.
- The semimembranosus generates the greatest peak force during the sprinting motion.
- The semimembranosus both generates and absorbs the greatest amount of power during the sprinting motion.
What’s going on with these results? Remember what is occurring during sprinting. At “foot off”, the heel is being brought to the athletes hip (thus the hamstrings all shorten). The leg is then swung forward. As it is swung forward, the heel begins to separate from the hip. As this is occurring, the leg is being driven down (i.e. the hip is being extended) so that the foot can make contact with the ground. This is why the peak length (and force) occurs just prior to footstrike.
According to the authors, most hamstring strains occur with the biceps femoris. This can be explained by the greater peak strain that it experiences during sprinting. It is interesting to me that the short and long heads of the biceps femoris function differently during sprinting, this may have some implications for conditioning.
While interesting, this study has limitations. First, you never know how sprinting technique (good or bad) influences the results. A different group of athletes (with better or worse technique) might have had different results. Second, a lot of the measures are based upon applying the observed measures to a mathematical model of the athlete, which always has limitations.
Schache, A.G., Dorn, T.W., Blanch, P.D., Brown, N.A.T., and Pandy, M.G. (2012). Mechanics of the human hamstring muscles during sprinting. Medicine and Science in Sports and Exercise, 44(4), 647-658.
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Comparing Elite Male and Female Weigthlifting Performance
In a previous post, I described a study that examined the kinematics of the snatch lift of the female world champions in the 2010 weightlifting world championships (see http://wp.me/p1XfMm-43). In that post, I described that there are a number of similarities to how male weightlifters perform the lift, but there were some differences as well. Erbil Harbili, in a recent issue of the Journal of Sports Science and Medicine, studied the lifts of the male and female 69-kg lifters during the 2010 world weightlifting championships. The author studied the heaviest lifts of the nine males and nine females in the A group of the championships. To give some perspective, the males averaged at approximately 68.5 kg in bodyweight and snatched an average of almost 149 kg (i.e. 2185 of bodyweight). The women averaged at approximately 67.9 kg in bodyweight and snatched almost 106 kg (i.e. 157% of bodywegith).
As with the previous study, the lift was divided into the following phases for analysis:
- First pull
- Transition
- Second pull
- Turnover under the barbell
- Catch phase
- Rising from the squat position
The study looked at the first five phases (first pull through catch). For the male lifters, this lasted about 1.35 seconds. For the female lifters it lasted 1.36 seconds. They both spent a similar amount of time in each phase:
| Phase | Male | Female |
| First Pull | .40 | .38 |
| Transition | .08 | .08 |
| Second Pull | .1 | .11 |
| Turnover | .17 | .17 |
| Catch | .24 | .26 |
There are differences in how the lift is being performed between the male and female athletes.
In terms of joint angles:
- During the first pull, the males have larger angles at the ankle, knee, and hip.
- During the second pull, the males have larger ankle and knee angles but smaller hip angles (though these are not all statistically significant).
In terms of angular velocities:
- The men are extending their knees and hips at a greater angular velocity than females during the first pull. The females are extending their ankles at a greater angular velocity during the first pull.
- During the second pull, the females are extending their knees, ankles, and hips at a greater angular velocity than males.
During the first pull, the men are generating greater levels of absolute power (i.e. watts) and relative power (watts/kg) than females. The males are generating almost 44% more absolute power, but only 2% more relative power during the first pull. In the second pull, the males are generating greater levels of absolute power (30% more), but lower levels of relative power than females (females are generating 7% more). The power output for the second pull averages to 19 or 20 watts/kg for males and females respectively.
Both females and males lift the bar to approximately the same heights during the first and second pulls. The interesting thing is that males are lifting the bar faster during the first pull than females (1.14 m/sec versus 1.03 m/sec), but females have an almost 7% faster barbell velocity during the second pull than males.
Now, these results should make sense. Women are achieving greater angular velocities during the second pull which should result in higher relative power outputs and a faster barbell velocity than males.
The author feels that the first pull results (i.e. joint angles) is due to the fact that female lifters are not as strong as the male lifters. The author also states that the greater extension values during the second pull for female lifters may be due to their greater flexibility.
These results suggest that female lifters don’t have the strength levels of their male counterparts and this is impacting how they perform the lift, particularly the second pull. However, female lifters may very well have some structural advantages when performing the second pull, which suggests that the future may become very interesting in this sport if their strength levels approach those of male lifters…
Harbili, E. (2012). A gender-based kinematic and kinetic analysis of the snatch lift in elite weightlifters in 69-kg category. Journal of Sports Science and Medicine, 11, 162-169.
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Analyzing the Performance of Elite Female Weightlifters
The snatch is an exercise that is frequently used in the strength and conditioning of athletes and is one of the lifts athletes compete in the Olympics. A great deal of research has been done on the snatch lift and male athletes, but not as much exists on female athletes. Hasan Akkus studied the performance of the winners of each of the weight classes during the 2010 world weightlifting championships. The athletes averaged out to be 24 years old, weighed ~66 kilograms, were ~165 centimeters tall, and lifted ~115 kilograms. The author analyzed the heaviest lifts in those weight classes. Two of the lifts analyzed were world records.
For analysis, the snatch lift was organized into the following phases:
- The first pull: Barbell lift off until the first maximum knee extension
- Transition: From the first pull until the first maximum knee flexion
- Second pull: From the transition until the second maximum knee extension
- The turnover: From the second pull until the barbell’s maximum height
- The catch: Maximum height until stabilization in the squat position
- Rising from the squat
The results of this analysis are interesting:
- The first pull was longer than the other phases.
- During the first pull, the knee angular velocity was greater than the hip and the ankle.
- During the first pull, the bar reached about 45% of its maximum height and almost 60% of its maximum velocity.
- The bar moved towards the lifters during the first pull.
- During the second pull, the hip angular velocity was greater than the knee and the ankle.
- During the second pull, the bar reached about 78% of its maximum height and its maximum velocity.
- The bar moved away from the lifters during the second pull.
- The power outputs in the first and second pull are very different than those reported for male athletes, at 9 and 29 watts/kg respectively.
Now, explaining the biomechanics. The first pull is typically a slow, controlled lift. A jerky first pull results in small mistakes that become magnified as the lift continues. During this time the knees are extending faster than the hips and ankles, which causes the bar to move close to the athlete’s body. This is important as it will ensure that the athlete has control of the bar later in the lift when it is overhead. The second pull can be likened to “jumping” with the barbell, there is a violent hip/knee/and ankle extension to power the bar to a great enough height so that the athlete can move underneath it. While all three joints are extending, it’s fair to say that the hip is the prime mover during the second pull. As the lifter is extending during the second pull, most lifters will move backwards some – this backwards movement typically forces the bar away from the lifter. If this is minimized it is fine, if this is exaggerated it results in a missed lift as the lifter can no longer get underneath the barbell. The second pull transmits the power to the bar to give it its maximum height (i.e. the “turnover” phase), at which point the lifter is moving underneath the barbell in a full squat.
The power output values are interesting. The first pull always has a lower power output than the second. However, the values (in relative watts/kg) are a lot lower than those reported for male weightlifters. The author postulates that this could be due to the relative “newness” of weightlifting for females (1987).
Akkus, H. (2012). Kinematic analysis of the snatch lift with elite female weightlifters during the 2010 world weightlifting championship. Journal of Strength and Conditioning Research, 26(4): 897-905.
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Postactivation Poteniation and Shot Put Performance
Larry Judge et al had a study in the March issue of Track and Cross Country Journal looking at post-activation potentiation (PAP) and shot put performance. The authors studied high school-aged female shotputters (best throw of 12.2 meters, mean bench press 81% of bodyweight, mean squat 199% of bodyweight, and mean power clean 81% of bodyweight). The idea behind the study was to examine the effects of throwing a heavier shot put prior to the competition shot. In theory, the heavier shot should have a poteniating effect on the competition shot performance if the timing is right.
After a fifteen minute warm-up, the athletes were randomly asked to perform three warm-up throws with either the 4kg shot (the competition shot), a 4.5 kg shot, or a 5 kg shot. Following the warm ups, the athletes performed three standing shot put throws with the 4kg shot.
The results showed that the heavier the warm-up implement, the worse the performance on the 4kg shot. Those athletes that warmed up with the 4kg shot had the best performance, those athletes that warmed up with the 4.5kg shot had throws that were 2% shorter than the 4kg group, and the group that warmed up with the 5kg shot had throws that were 4% shorter than the 4kg group.
In an excellent discussion, the authors raise a number of important thoughts about post-activation potentiation and the results of this study. First, it may not work. Second, to be effective it may require a certain level of strength and experience. Third, it’s very likely that to be effective this is something that has to be practiced before it is suddenly introduced prior to competition.
To a point I agree with the authors and I think there are a number of factors that need to intersect for PAP to be successful. I agree that there probably has to be a certain strength level present for this to be effective. This is certainly true with other exercise modes (for example, plyometrics are more effective for stronger athletes). This speaks to this being more of a tool for advanced athletes. Second, the idea that it works better after it has been practiced make a lot of sense and this is something I’d really like to see studied in the future. It’s like any training tool, you don’t want to do it for the first time just prior to the big competition. Third, I think there’s a very individualized timing issue with PAP. Studies show that everything from a few minutes between the exercises to eight minutes rest between the exercises is what is required to make PAP most effective. I think this is going to be different for every athlete and requires some trial and error to figure out (which reinforces the need for practice).
Now, I also think this is something that a lot of people want to be true (i.e. PAP works) no matter what and this makes them blind to some of these factors.
Judge, L.W., Bellar, D.M., Judge, M., Gilreath, E., Bodey, K.J., and L. Simoni. (2012). Efficacy of potentiation of performance through over weight implement throws on female shot putters. Track and Cross Country Journal, 1(4), 9-18.
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Drills To Increase Top Speed
Being able to increase speed is important to just about every athlete and coach. Speed helps to determine success in almost every sport and position, is evaluated to determine if you make the team, and being able to increase speed is something that almost everyone desires. Speed is primarily evaluated with moderate sprints, like the 40 yard dash. This article will present some drills to help you increase speed.
40-80 Yard Sprints:
Sprinting at high speed is a skill that you have to practice to get good at. Unless you are an elite 100 meter sprinter, it will take you 20 to 40 yards to get to your maximum speed. Longer sprints (40 to 80 yards) are designed to help you practice reaching maximum speed and trying to maintain it. Several things are important with these longer sprints:
- Warm up thoroughly before these sprints. Longer sprints increase your risk of a hamstring injury so it’s important to warm up.
- Use good technique. If your technique suffers then all you do is reinforce bad habits.
- Keep the volume down. Too much volume gets you tired, which teaches you to be slow and sloppy.
- Recover fully between each sprint. Failing to recover properly gets you tired, see above about being slow and sloppy.
These sprints should be done no more than six to ten times during a speed workout with full recovery between each sprint. Focus on technique, speed, and explosiveness.
Stride Length Drills:
To be able to run faster, you need to take longer strides. This drill helps you to lengthen your strides. For this drill, you need four cones, hurdles, or something that can serve as a visual marker for you while you sprint. Set up the first cone twenty yards from the start line. Place the second cone four paces from the first. Place the third cone six paces from the second. Place the fourth cone eight paces from the third. Go to the start line and get in your ready position. Sprint to the first cone. When you reach the first cone, sprint so that you place one foot in between each cone. After clearing the last cone, sprint for five to ten more yards.
With this drill, remember that even at the longest distances, you need a natural stride. Placing the cones too far apart will disrupt your sprinting technique. If you find yourself leaning backwards then the cones are too far apart. Perform this drill three to five times as part of your sprint workout.
In’s and Out’s:
This drill teaches you to run relaxed at speeds and it teaches you how to shift gears while sprinting. For this drill, you need seven cones. Place a cone at the start line and every ten yards. Stand at the start line and get into your ready position. Sprint to the ten yard line, this is your acceleration zone. Between the ten and twenty yard lines, sprint as fast as you can. Between the twenty and thirty yard lines, back off a little and try to coast. Between the thirty and forty yard lines sprint as fast as you can. Keep alternating until you have run through the finish line at 60 yards.
This is a very tiring drill. It’s important to warm-up properly and pay attention to your sprinting form throughout. If you do this as part of your sprint workout, it should be the only sprinting exercise you do that session. Perform this no more than three times in a workout, resting completely in between each attempt.
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Classic Article: Elastic Energy, Opposing View
In a previous post (http://wp.me/p1XfMm-3S), I covered an article that dealt with elastic energy. Not all sport scientists accepted the concept of elastic energy. One of the leading opponents to this concept was a biomechanist named Gerrit Jan van Ingen Schenau, who died in 1998 effectively ending the debate.
In a 1984 paper, he reviewed the concept of elastic energy, presented some arguments against it, and developed an alternative hypothesis.
The author begins by presenting the other side of the argument, i.e. the case for the existence of elastic energy. He begins by reviewing studies that show that isolated muscles can do more work during concentric contractions when they are stretched previously and studies that show that external force and work output in multi-joint movements are increased when a movement is preceded by a counter-movement. He also presents a very interesting case for the existence of elastic energy due to the fact that the power outputs seen during running can only be explained by the storage and re-utilization of elastic energy.
With his arguments against elastic energy, the author begins with the equation for determining the work done by a body. The equation shows that a muscle can only do work if force is exerted on the environment and if the muscle shortens. On the other hand, the environment can only do work on a muscle if the muscle’s length increases under the influence of a force. This is important because the muscle cannot re-use elastic energy which was not previously stored when the environment acted on the muscle. In other words, there is only a finite amount of elastic energy that can be developed, stored, and re-used. This argument is being made because, according to the author, it is impossible to generate the amount of elastic energy that is attributed to this phenomena by the equations.
The author then shifts to discussing where elastic energy can be found. According to the author, in the muscles elastic elements are only located at the cross bridges. If muscle elasticity is only located at the cross bridges than it can only be stored if the cross bridges are attached – once they are detached then the energy is lost as heat. So based upon this, the muscle isn’t a viable location for “where” elastic energy is stored. Tendons represent a good alternative, but they are stronger and stiffer which means that they would store less elastic energy, particularly at higher strain rates.
So, the author’s principle concern is that it doesn’t seem possible to generate and store the amount of elastic energy that would be necessary to improve performance as much as is attributed to it. If this is true, what accounts for the improvements in performance that a counter-movement causes? Van Ingen Schenau goes into a long analysis of cross-bridge activity during a muscle contraction, but his point boils down to this: A pre-stretch makes more cross-bridges available during the subsequent concentric contraction than without a pre-stretch.
This paper, and others that his author wrote, represents a fascinating alternative to something that we “know.” In fact, the November 1997 issue of the Journal of Applied Biomechanics was devoted to elastic energy and there are a number of great papers in it including several by Van Ingen Schenau. Unfortunately the author died in 1998 and it seems that the debate died with him.
Van Ingen Schenau, G.J. (1984). An alternative view of the concept of utilization of elastic energy in human movement. Human Movement Sciences, 3, 301-336.
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Classic Article: Elastic Energy
The concept of elastic energy is something that is a foundation behind athletic performance. It is important for throwing, kicking, jumping, running, etc. The idea behind elastic energy hinges on the fact that muscles don’t “want” to be stretched out. When a muscle is put on a stretch, after a certain point it begins to contract on its own as part of a protective reflex (the so called stretch reflex). A muscle that is put on a fast stretch, immediately followed by a fast contraction, is able to use the stretch reflex to produce more force than it would have been able to otherwise – this is called elastic energy.
I’m going to devote the next few classic articles to elastic energy. While this is something that we accept and put into strength and conditioning practice, it has not been universally accepted. However, with the death of the principle critic (Gerrit Jan van Ingen Schenau) in 1998, much of the debate has ended.
In 1978, Paavo Komi and Carmelo Bosco published a paper in Medicine and Science in Sports and Exercise looking at the impact of different jumping conditions on performance. They studied almost 60 subjects divided between female university physical education students, male university physical education students, and male national-team volleyball players.
The subjects performed vertical jumps on a force platform under several conditions:
- Squat jump: The subject squatted to a 90 degree knee angle, held the position, and performed the jump without a counter-movement.
- Vertical jump with a counter-movement
- Drop jump: Drop from a height to the force platform and quickly jump upwards.
Drop jump height differed for females (20, 30, 40, 50, 60, 70, and 80 cm) and males (26, 45, 62, and 83 cm).
On all jumps, the subjects kept their hands on their hips.
The results are mixed and are interesting:
- The female subjects performed as you’d expect. Squat jumps resulted in a lower maximum height to the center of gravity than the counter-movement jumps. The counter-movement jumps resulted in a lower maximum height than the drop jumps.
- The male physical education subjects had a lower squat jump height than counter-movement jump and drop jump. However, the counter-movement jump and drop jump heights were equal.
- The volleyball players had a lower squat jump height, but their counter-movement jump height was greater than their drop jump height.
- The volleyball players, for all tests, jumped higher than the male physical education students, who jumped higher than the female subjects.
In addition to looking at the height of the jump, the authors also measured energy output. They found that:
- Counter-movement jumps have a greater positive (i.e. takeoff) energy than squat jumps for all subjects, with females < male PE students < male volleyball players.
- For all subjects, the positive energy increased during drop jumps as height increased to a certain point and then leveled off (~50 cm for females, ~62c, for all males) and this equated to the heights where the best drop jumps were achieved.
- On drop jumps, females had a greater change in positive energy (i.e. compared to squat jumps) than males.
The table below shows the change in positive energy as a percentage of the positive energy during the squat jump for the counter-movement jump and the highest drop jump for each population. As you can see, the female subjects had a greater change in positive energy.
| Female | Male PE | Male VB | |
| CMJ |
0.206835 |
0.13529 |
0.166611 |
| DJ |
0.323741 |
0.084604 |
0.07784 |
For elastic energy to work like we think it does, you’d expect for squat jump heights < counter-movement jump heights < drop jump heights. The female group is the only group that saw this. In the other two groups, squat jump heights were lower but the counter-movement jump heights were equal to or greater than drop jump heights.
The authors feel that the greater positive energy change in the female athletes represents a better ability to utilize stored elastic energy, but are unsure why this is the case.
It’s an old study. It shows that jumps that are performed without any kind of counter-movement are smaller than those with the counter-movement. However, from that point the results are a little confusing, which leaves room for debate on the concept of elastic energy. While there is certainly an increase in performance following a fast stretch and fast contraction, the exact mechanism (in this study) remains to be determined.
Komi, P.V. and Bosco, C. (1978). Utilization of stored elastic energy in leg extensor muscles by men and women. Medicine and Science in Sports and Exercise, 10(4): 261-265.
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Hamstring Strain Injuries: Dispelling Myths and Food for Thought
The journal Sports Medicine has a review in the March issue on hamstring strain injuries (HSI’s). Beginning with the premise that despite our knowledge of injuries and strength/conditioning, HSI’s are not declining. Beginning with that premise, the authors state that what we know needs to be reviewed as something in the practice of injury prevention/rehab isn’t working.
According to the authors, depending upon the sport, HSI’s account for 12-26% of all injuries. In addition, at least a quarter of those are re-injuries. The majority of HSI’s occur when running, primarily during the “terminal swing” which is the time during which the hip is flexing, the knee is extending, and the hamstrings are firing (while lengthening) to keep the knee from hyperextending.
The authors identify risk factors for HSI’s and classify these as unalterable and alterable. The unalterable ones include age, previous injury, and ethnicity (Aborigininal, black African, and Caribbean ethnicity may be risk factors). The alterable ones include strength imbalances, flexibility, (the authors cannot find evidence that poor flexibility contributes to hamstring injuries), and fatigue.
The article concludes with looking at how effective training is at preventing HSI’s. Essentially the authors state that eccentric training studies are inconclusive, Since flexibility doesn’t seem to be associated with hamstring injuries, the authors don’t find that flexibility training reduces hamstring injuries.
Now, an interesting point is that there may be “maladaption” as a result of hamstring injuries. They use ACL injuries as an example. After an ACL injury the maladaption is that the athlete is unable to achieve the same voluntary activation of the knee extensors, sometimes for years after the injuries. The idea here is that this may explain the significant re-occurrence of injury though this has not been studied.
I find the authors’ points about flexibility really interesting. Another example about how the literature frequently conflicts with what we “know.” The maladaption point is an interesting one and represents something that warrants further study.
Opar, D.A., Williams, M.D., and Shield, A.J. (2012). Hamstring strain injuries: Factors that lead to injury and re-injury. Sports Medicine, 42(3): 209-226.
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Exercise Order Impacts Performance
Over the years I have found the journal Sports Medicine to be a good source of information. This journal publishes reviews on significant topics. The current issue has a review on exercise order for strength training. Conventional wisdom on this topic is that exercise should be ordered as follows:
- Explosive exercises (i.e. Olympic lifts, squat jumps, etc.)
- Large muscle multi-joint exercises (i.e. squats, deadlifts, presses, etc.)
- Large muscle isolation exercises (i.e. flies, lateral raises, etc.)
- Small muscle exercises (i.e. triceps pushdowns, curls, etc.)
Of course, there are always exceptions. For example, there are instances where an explosive exercise would be performed after a heavy large muscle multi-joint exercise (squats followed by vertical jumps) or where an isolation exercise would precede a multi-joint exercise (flies before bench press). A lot of this comes from coaching practice and, while I “know” it works, there’s not necessarily a lot of easily accessible research on this.
Simao et al, in the March issue of Sports Medicine, performed a literature review on exercise order and strength training focusing both on the acute response (i.e. that training session) and the chronic response (how it impacts strength and hypertrophy).
Acutely, the authors found that where an exercise is located within a strength training session has an impact on the total number of repetitions that can be performed with that exercise. In other words, if an exercise is at the end of the workout the athlete will be able to perform fewer repetitions with it as the athlete will be fatigued. The authors did not find that pre-exhaustion (isolation exercise performed before multi-joint exercise) has any impact on muscle recruitment patterns.
Chronically the results are a little mixed (according to the authors). In the studies they review, those exercises that are performed at the beginning of a workout are the ones that make the most significant strength gains over the course of training. In terms of hypertrophy, the studies reviewed are only looking at biceps and triceps. Triceps hypertrophy seems to be better when isolation exercises are placed at the beginning of the workout than when they are in the end.
The fact that fatigue impacts number of repetitions and chronic strength gains isn’t surprising. It is interesting that pre-exhaustion has no impact on muscle recruitment. The idea that we’ll make better strength gains on the exercises that are performed at the beginning of a workout (because we can train it harder) is also not surprising.
Now, there are major limitations to these kinds of studies. The studies that the authors reviewed generally focus on upper body exercises and assume that all muscle groups are trained in every workout. The workouts look like: bench press, pulldowns, triceps extensions, and biceps curls. This would be an effective workout for an untrained individual, but does not generally reflect what a trained athlete’s workout is going to look like. The chronic studies only looked at hypertrophy of the biceps and triceps. All of the exercises studied train either the biceps (pulldowns and curls) or triceps (bench press and extensions), whereas only the bench press trains the chest and only the pulldowns train the upper back. It would be interesting to see how these studies impacted pectoralis major or latissimus dorsi hypertrophy.
Simao, R., de Salles, B.F., Figueiredo, T., Dias, I., and Willardson, J.M. (2012). Exercise order in resistance training. Sports Medicine, 42(3), 251-265.
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