Caffeine For Strength Training: A Review and Opinion

Much has been researched on the beneficial effects of caffeine for endurance/aerobic training. There are too many articles supporting these claims to make listing them reasonable. There is a reason why the IOC, NCAA and USTAF have strict restrictions and blood testing protocols for caffeine; it simply works. The rationale behind this is that caffeine helps facilitate free-fatty acid metabolism preferentially over glycogen and other carbohydrate homologs in the body. Fat generates a higher yield of ATP with a subsequent lower production of lactate, which is needed in long duration aerobic exercises. In addition to these metabolic effects research has shown caffeine to provide a temporary analgesic effect, which is extremely beneficial to endurance athletes during the final legs of their races when they are pushing themselves and likely utilizing anaerobic systems which can be painful. Cyclists have realized this analgesic effect for years as they used to fill their water bottles during races with flat cola. in addition to these effects, caffeine is a brochiodilator and also allows the diaphragm to contract more forcefully this is why pulmonary therapists administer caffeine to patients prior to treatment.

In a review published by McCormack and Hoffman in this July’s Journal of Strength and conditioning they highlight the potential benefits caffeine may provide for power and strength training. The mechanisms they attribute to the positive effects caffeine may provide are neuromuscular and central nervous system mediated. The CNS effects are founded under caffeine’s stimulant properties by blocking adenosine receptors which alters the perception of fatigue, improves focus and reaction time. Due to these effects, caffeine has been used as an alternative to amphetamines in USAF pilots flying repeated missions who require the mental acuity and sustained reaction time to complete a tactical flight operation.

The neuromuscular effect is mediated by enhanced excitation-contraction coupling through the Treppe effect. The treppe effect improves neuromuscular transmission by increasing the mobilization of intracellular calcium ions from the sarcoplasmic reticulum which is required in for the cross bridging between actin and myosin heads which produce a muscle contractions. Caffeine is also thought to enhance the kinetics of glycolytic regulatory enzymes, which are active in strength training activities, such as phosphorylase. The results of these metabolic and neuromuscular effects appear to allow the muscle to not only produce a more forceful contraction but also increase the number of repetitions per set. There have also been studies that have found caffeine if ingested acutely after a bout of exercise, (in the highlighted study’s case it was short duration high intensity intense cycling) recovery had improved as compared to a placebo on a quadriceps strength test.

Though the authors did report evidence that caffeine ingestion may be beneficial for strength and power training it appears though that the results are inconclusive as to whether or not caffeine in isolation results in these effects. The majority of these studies administered caffeine in the form of an energy drink or some sort of caffeine-proprietary nutrient concoction. The most common additives are taurine, beta-alanine, creatine and other amino acids; all of these supplements have shown to improve recovery and endurance to varying degrees. There also appears to be a dosage effect as well as most of the studies that resulted in improvements administered caffeine at the dosage of 5-6mg/kg body weight. Which if you consider that per 8oz of liquid redbull contains 80mg, coffee contains 110-150mg, and cola contains 30-40mg; so you may have to consume a considerable amount to get these effects much more than most have ever consumed.

Although these results are encouraging for the usage of caffeine for strength training purposes, in my professional opinion I would tread with caution. Caffeine can be rather dangerous to someone if administered in these high dosages without proper cardiovascular testing. Caffeine is sympathomimetic drug, which means it provides effects similar to those caused by the sympathetic nervous system which will increase HR, BP and blood flow to the skeletal muscle, amongst other effects. If someone who had an undiagnosed problem or defect were to ingest caffeine with these recommended dosage rate serious problems could occur. So it would be best to consult your physician before initiating a dosage regimen and have a physical therapist monitor you the first few times you exercise to monitor for deleterious effects/changes. Secondly, though the authors sited evidence of improved strength and power upon further review of the literature a lot of the studies they cited had subjects exercise to exhaustion or tested them on isokinetic strength tests. Tests to exhaustion are not a reliable or valid measure of strength or power and isokinetic testing does not assess the patient in functional movement pattern or at an angular velocity consistent with normal movement. In summary the evidence isn’t that strong to suggest direct strength and power gains but it may improve both factors in an indirect way, which I will elaborate on.

As most people in the field of sport performance and nutrition know most of the focus for supplementation is focused around recovery. Caffeine does directly improve recovery probably due to the increased, cardiac output and perfusion to the skeletal muscle. These cardiovascular effects will help remove metabolic waste products away from the muscles to the liver and help bring nutrients to the muscle. The authors however did not mention the benefit of caffeine as a moderate bronchodilator on training. If the bronchioles are more dilated it will improve ventilation to help buffer out the drop in ph due the shift in the strong ion difference following an acute bout of exercise. Similar to other supplements caffeine does show to improve the amount of repetitions a person can perform due to the previously mentioned improved blood flow and analgesic effect. If someone can decrease the soreness they feel during a max lift or increase the amount of repetitions they can perform, strength will improve over time.

In short caffeine like many other supplements helps you work out longer through it’s metabolic, cardiovascular, neuromuscular and central nervous system effects. It helps improve muscle metabolism by improving blood flow to the muscle, ventilation, focus and decreases pain. Dosage should be close to 5-6mg per kg body weight and administered 45min prior to exercise or immediately after.

Thanks for reading!

Here is a link to the article

http://journals.lww.com/nsca-scj/Abstract/2012/08000/Caffeine,_Energy_Drinks,_and_Strength_Power.3.aspx

Jump training and knee valgus angle: A review and opinion

ACL injuries and other such knee ligamentous pathologies are by far some of the more common and more devastating injuries in sports. Each year 2,220 ACLs are expected to be torn just in female college athletes alone with basketball players having the highest percentage. Some people attribute this preponderance of injury in women to a number of factors including narrowness of the intercondlylar groove of the knee, strength, flexibility and endurance. However, the current literature seems to consider jump landing strategies as function of neuromuscular control to possess the strongest causal link. This idea is reasonable as the mechanism of injury for ACL tears are deceleration/change of direction non-contact injuries with the foot planted. Thus if an athlete lacks control at the knee each time he/she lands the force from impact would be placed passive structures since the active structures don’t fire correctly thus potentiating the risk of injury to ligaments etc.

Due to this knowledge jumping programs focusing on correcting the valgus angle or frontal plane strategies have been initiated. These programs have had success but what researchers, therapists and coaches have trouble with is finding a way to fit these jumping programs into existing strength and conditioning programs. Most studies for valgus prevention utilize programs that last 6-8 weeks and each session can last 20min-1hr, which in the realm of athletics is too long to add to what typically is a very tightly scheduled regimen and programs that long may present problems with compliance . What Lee Herrington’s study examined was whether or not a program in 4 weeks, 2 times a week, for 20min per session could result in the same benefits of the longer jumping programs.

The study took place in Manchester, UK and the subjects were 15 female collegiate basketball players with no history of ACL or other such knee pathology. He evaluated knee “function” through three measures; 1) knee valgus upon landing from a depth jump to simulate a player landing from grabbing a rebound or finishing a shot, this was done via a digital video recording 2) He had the players run from half court to the foul line and shoot a jump shot, this was done to evaluate the players in a functional movement pattern specific to their sport and since the players would more likely concentrate on making the shot it than jump “correctly” which would expose their more normal jumping and landing strategies. Again the valgus angle was recorded via a digital video recording 3) The players were tested on lower extremity power by having them perform a cross over jump test. The test required the players to jump on one leg on diagonals across a line three times with the goal of traveling the farthest possible with 3 reps/jumps.

All subjects were evaluated on all 3 measures at pretest and then initiated a jumping program where they were first educated on how to land correctly with the knees in line in a “sagittal plane strategy” and performed all exercises with close monitoring for form. The program consisted of various plyometric and agility exercises with some basic strength components as well. All subjects completed between 10 to 12 sessions and were all instructed not to perform additional training on the day of each session. The researchers evaluated the test retest reliability for each measure on 5 players independent to the study to evaluate for error and all were found to have high reliability and very small amounts of difference between measure for each recording. The minimal statistical change for the depth jump was 1.2deg, 2.2deg for the jump shot, and 79cm for the cross jump test.

Upon post-test the results were quite impressive. The valgus angle during the depth jump on average decreased by 9.3deg on the left and 12.3deg on the right; the the jump shot valgus angle on average decreased by 4.3deg on the left 4.5deg on the right; for the cross jump test the left improved by 111cm and the right improved by 110cm. All of these results were significant to a p level of 0.05.

Though the subject size was relatively small and this was only tested on women it is not completely generalizable but for the athletic female population this is very applicable. And again other studies that had similar programs but were longer in duration produced benefits of similar magnitudes which suggests that these results are reasonable. The fact that this duration is effective also falls inline with accepted contemporary theories on strength training in that the early gains (under 6-8weeks) in strength and function are more based on neuromuscular adaptations rather than muscle hypertrophy. One must also consider again that since this study was done in a much shorter amount of time future programs like this should have less of a problem with patient compliance. In the future I would like to see a study that evaluates the results of a jump training program conducted in 4 weeks and evaluate the valgus angle 4 weeks after completion of the program to asses the retention of these skills and compare those to a training program under a longer treatment duration. A study analyzing the trend in valgus angle decreases after a 4 week program that continues to 8 weeks would be useful as well to see if the benefits constantly improve with training or if they plateau and to see if the problem lies within motor control vs muscle girth/weakness.

From a clinical aspect these results have huge ramifications for our profession. Injury prevention and performance are two avenues where therapists have the best skill set to make the highest impact. These results can be used as a selling point to coaches because not only do programs such as this prevent injury they have also demonstrated improved performance in relatively a short amount of time. Personally I would like more research to be conducted to further justify this compressed training schedule and programs for other joints such as the shoulder, back and hip. The more we can demonstrate the benefits of preventative interventions the more likely insurance will cover it especially if we can reduce risk with less cost per patient. This will not only provide more avenues for business but it will help our patients in the long run. Research drives reimbursement from insurance and reimbursement drives practice.

I have always stood by the belief that its cheaper and more efficient to prevent a problem than to fix it. Think about it, if you maintain your car and check the oil regularly and brake fluid it will cost you substantially less than paying for it when one of those components fails or in the worst case you have an accident. The same can be said about the human body, if you maintain the body and keep it healthy you can prevent tissue failure and prevent serious injury.

Included are some images of the results on pre and post test. More images to follow.

here is a link to the article

http://www.ncbi.nlm.nih.gov/pubmed/20664369

Have a great day!

-Rich