Cardiovascular Conditioning: adaptations to aerobic training

This piece is written for those with little background in exercise physiology, breaking concepts down as much as possible without losing the integrity of the general concept, adaptations our body makes to aerobic training. For health, safety and performance sake, however, I feel it needs to be made clear from the outset that aerobic training is not the “be all and end all” in taking care of our bodies. Other types of training are necessary for a variety of health and safety reasons. Emphasizing only aerobic training can compromise our ability to respond to emergency situations with the speed and power necessary to protect ourselves and can prevent us from maintaining tissues that have the type of mass, flexibility and elasticity needed to respond with quick movements and absorb minor fall. Please feel free to ask me or your trainer more about this.

Cardiovascular Adaptations

Aerobic training, as the adjective implies, develops our ability to utilize oxygen in processing energy. The aerobic response in the body involves the nervous, endocrine (hormonal), cardiopulmonary and muscular systems most directly. The ability of the heart to transport oxidized blood to the muscle tissue is the dominant and easiest response to measure. With the appropriate stimulus, the primal part of our brains triggers a neural and hormonal response that dilates the arteries that supply the skeletal muscles and constricts those that supply less essential structures. Neural and hormonal responses also trigger the heart to expand as fully as possible and contact as forcefully as possible to bring in as much blood as possible and push out as much blood as possible. The complete filling of the heart causes this muscle to stretch to its fullest capacity, therefore enhancing the expulsion blood by way of an added elastic release to the powerful muscular contraction. This allows more blood to be ejected with fewer contractions. This characteristic is maintained and developed in the cardiovascular system with training, so that at rest the heart will continue to need fewer contractions to provide the body with the oxygen it needs to process energy. This, over time, presents itself as a lower resting heart rate in aerobic athletes.

Energetic Adaptations

The advantage behind supplying so much oxygen so quickly to the muscles is that it allows for a very efficient energy processing system called the oxidative system. This system can produce a lot more energy than the other two major energy systems in our body and better utilizes more fuel sources. Aerobic training encourages the production of those enzymes that aid in the oxidative process, allowing the breakdown of carbohydrates and fats to produce energy.

Neuromuscular Adaptations

Processing energy using large quantities of oxygen happens in the muscle cell within an organelle called a mitochondria. This is a complex structure and in itself requires considerable resources. Some muscle tissues are better adapted to utilizing mitochondria. These are the type I muscle fibers. Aerobic training emphasizes the development of type I muscle tissue. As training continues, muscle filaments and neural connections that are deemed as unnecessary in the type I muscle fibers are replaced with mitochondria to process oxygen. Collagen (a light, tough element in the connective tissue) is added to support the muscle cell in the absence of contractile filaments.

The Overall Result

With continued aerobic training, the athlete develops a cardiovascular system that can transport great quantities of oxygen to an oxidative system that supplies the enzymes that produce energy within very light, efficient muscles that are able to produce movement over and over again for long period of time without rest.
This is perfect for the distance runner and has health benefits for us all but, as stated above, it should never be the only form of exercise one gets. It can diminish flexibility, strength, balance and power (the ability to respond quickly with strength) and by itself is not the best way to lose weight or maintain a healthy weight or body mass.

For the complete story…

The above explanation has gaps big enough to drive a truck through. The full story covers a couple of hundred pages in an exercise physiology book and it’s probably best if you’ve had your biology and chemistry before reading it. If you have any questions about this or the body’s adaptation to different types of training stimuli, feel free to book an appointment with me.

Cardiovascular Conditioning: Maximum Heart Rate

Most people and most athletes don’t fully understand the relationship of cardiovascular to their training goals. We’ve had a string of over-training injuries and conditions during August. Cross country runners pumping out 100 mile weeks and soccer players determined to toughen up quickly with excessive road work, to name just a few. This is no surprise – aerobic training is addictive, easy to do and it is not a simple subject to understand. Even the rationale for the standard formula currently accepted for maximum heart rate is questionable for training purposes. Since the gyms seem to be full of people wearing fashionable heart rate monitors, maximum heart rate seems like a good starting point,  for athlete and non-athlete alike, to better understand the cardiovascular response to training in their bodies.

MHR = 220 – age

The standard formula for maximum heart rate (MHR) and its derivatives is MHR = 220 – age. It’s so commonly used in the training world one would think the scientific foundation for the statement was solid and profound and absolutely the last word. It’s none of the above. The equation was derived in the 1960’s from an observation of data Dr. William Haskell had collected and graphed from a study about heart disease. The subjects were male, under fifty, not in particularly good shape, and many smoked. The original goal of his study was to determine just how hard heart disease patients could push themselves and was not designed at all to evaluate healthy individuals or conditioned athletes. So, how did it become "law"? It wasn’t the study, but the timing of its release. Cardiovascular training was just becoming popular in gyms and on the streets (I can still remember neighbors teasing me, yelling “Hey, what are you running from?” when running in 1968!). Doctors and trainers were hungry for an answer to the question “How hard should I run?”. The formula stuck. Not very scientific when it comes to training perhaps, but whole industries grew up around it so it’s probably going to be in people’s repertoire for a while.

For training purposes we like to manipulate different physiological responses within the body which we know are related to how oxygen is exchanged, which can be roughly related to percentages of the maximum heart rate. Therefore, a Target Maximum Heart Rate formula (TMHR - a percentage of the MHR) is used to target these changes.

For example:

A 40 year old woman is instructed to run at an intensity of 75 to 80% of her maximum heart rate.

TMHR(lower limit) = (220 – 40).75 = (180).75 = 135bpm (or about 23b/10sec)
TMHR(upper limit) = (220 – 40).80 = (180).80 = 144bpm (or about 24b/10sec)

Now for my money, if we are going to use a set formula like this, we need to be looking for the percent of change between the minimum heart rate (resting heart rate, RHR) and maximum heart rate. We can then add in the resting heart rate at the end to provide us with a real countable beats per minute number.

Therefore, that same 40 year old female athlete with a resting heart rate of 60 beats per minute would be:

TMHR(lower limit) = (180 – 60).75 + 60 = 150bpm (or 25b/10sec)
TMHR(upper limit) = (180 – 60).80 + 60 = 156bpm (or 26b/10sec)

One of the reasons this formula has stuck around is that it is relatively safe for the average person. For general conditioning purposes, however, it has been suggested that rate of decrease in heart rate from maximum heart rate to resting heart rate after exercise might be a better indicator of when to increase the intensity of an aerobic workout. That is, in general, how long does it take your system to recover is a better indicator of your health and conditioning. In training athletes, perceived exertion levels are often used instead of specific heart rates, which really does make sense, especially with elite athletes whose heart rates often don’t fit the MHR format at all.

One final note – don’t trust the built-in heart rate monitors in the cardio equipment at the gym. The accuracy varies wildly – depends on the machine and the gym maintaining them. Check it yourself. Yes, your calculations are correct – the machine is wrong.

In future blogs, we will examine the specific changes cardiovascular training promotes in the body.

References Utilized:

1. Ultimate Fitness
     Kolata, Gina Farrar, Straus and Giroux 2003 NY, NY

2. Essentials of Strength and Conditioning, 2nd Edition
    Baechle, Thomas R., Earl, Roger W. Human Kinetics 2000 Champaign, IL

Vision Tests: Saving Life & Limb

When addressing the topic of preseason pre-habilitation and competition readiness, a thorough screening and testing of athletes usually involves routines that check the cardiovascular, neuromuscular and connective tissue response to the demands of an athlete’s particular sport. One aspect that is often underappreciated is a thorough vision exam. A thorough vision exam is essential to insure optimal performance by the athlete and provide the highest degree of safety for the athlete. This is more than being sure that an athlete can read black-on-white lettering at 20 feet. In fact, bringing the athlete up to the 20/20 in most cases should not be the standard, but just the starting point.

There are four aspects of vision that an athlete should be checked for, their sport depending on how heavily to weigh the results: visual acuity, peripheral vision, contrast sensitivity, depth perception.

Visual Acuity – how clearly can an athlete see? Black-on-white clarity. Essential starting point.

Peripheral Vision – this is visual awareness outside of direct line of sight. All the plyometric exercises and agility drills won’t prevent an ACL injury or a concussion if an athlete can’t see a lateral hit coming.

Contrast Sensitivity – this is the ability to detect the subtle difference is shades of color. The shade of color a moving object or an angled object can make a huge difference in split second responses by the athlete.

Depth Perception – crucial for performance (quarter back) and safety (gymnast).

These tests take very little time and every second they do take is a valuable investment in the safety and success of our athletes.

If your organization does not offer these preseason vision screenings, please visit www.aoa.org/x5428.xml to find a doctor in your area.


References Utilized:

www.aoa.org

Prehabilitation: Hamstring

One of the most frustrating injuries for any athlete to overcome is the hamstring strain. A strain can occur anywhere in the muscle but most commonly lesions can be found near the musculotendinous junction of the muscle/tendon unit. This is due to several factors. Two of the most important factors are inefficient recruitment patterns of the lumbopelvic (lumbopelvic core) musculature in gait and the accumulation of scar tissue in vulnerable areas of the muscle due to injury.

These two factors can be independent factors but often work together to cause injury and reinjury. It is not uncommon, for example, for a distance runner to have weak hip stabilizers, causing stress along the distal aspect of biceps femoris and the iliotibial band due to over reliance on gluteus maximus and tensor fasciae latae or for a field hockey player to experience to experience pain in her proximal left biceps femoris due to her right hip flexors being locked short. Once these patterns lead to injury, the accumulation of scar tissue near the musculotendinous junctions by itself make these points vulnerable to reinjury but may also interfere with the proprioceptors in the region possibly reinforcing and exaggerating the patterns that caused the injury in the first place.

Taking action before an injury occurs (prehabilitation) is always your best option. Appropriate core training and warm-up for the sport (which crosses a wide spectrum of training from weight training through plyometrics and active warm-ups) can strengthen the necessary structures and prevent overdependence on patterns that cause hamstring injuries. Manual therapy to open and loosen the muscle and break down the accumulation of scar tissue and resolve adhesion may also decrease the probability of injury. Once an injury has been incurred, both these procedures become important to the rehabilitation process as well.

If you want to know more about your specific hamstring injury and how to heal it more effectively, please schedule an appointment by visiting www.soarbody.com.

Prehabilitation: Resistance Training

The summer season is post-season for many of my collegiate athletes, the perfect healing time to rebuild and rebalance some of the overworked structures in their bodies with resistance training. This is an extremely important phase in the training cycle for injury prevention as well as for performance. Adhering to a resistance training program appropriate for your sport is essential during this period.

Utilizing a personal trainer to help tweak the program your CSCS provided you is my first recommendation for a successful post season. With their expertise and objective perspective they can detect dysfunctional patterns that we cannot see in ourselves and they have the tools to get the job done at their disposal. If your CSCS is also a personal trainer and has hours available to you, that’s even better since they have specifically studied your sport (and often participated in it in college!).

If you feel going it alone this summer with the training program you have been given is your only option, follow it carefully and consistently. Most of the resistance programs that have been brought to me to review make sense in their structure and frequency. They do seem to assume the athlete knows the correct exercise sequence. Correct exercise sequence is important not only for optimal development but also for injury prevention. Dysfunctional patterns can develop through compensation due to fatigue. Strains, and trauma due to accidents, can also occur as a result of trying to perform the wrong exercises in a fatigued state. Below is listed an exercise sequence designed to protect the athlete and allow them to develop their greatest potential by themselves. (1)

1. Explosive whole power body lifts: Power cleans, Snatch, etc.

2. Multi-joint exercises: Bench press, squats, shoulder press, seated row

3. Single joint exercises: Triceps extensions, knee extensions, biceps curl
 
This may seem trivial to some, especially with the complexity of some of the more elaborate functional exercises woven into their programs as they progress, but the sequence is extremely important.

A final note: great form is essential. One of the themes of post/off season training is to correct, to some degree, the dysfunctional patterns developed by the athlete during the season through repetitive movements and postures necessary for their sport. This is something we always must work to perfect. If you cannot afford the time or money to employ a personal trainer, please book an appointment with me for a functional movement screen. This is not a substitute for a good personal trainer, but it can identify your major functional weaknesses so you can work on them to help prevent injury. If a personal trainer is an option for you, I’ve listed some of the best local independent trainers (they work in training facilities – no membership required) in the Cambridge/Somerville area below.

Maren Kravitz and Heidi Brown, The Training Room, Porter Square, Somerville
http://thetrainingroomboston.com/tr/home
 
Callie Durbrow, Durbrow Performance, Central Square, Cambridge
http://durbrowperformance.com

References:
1. Essentials of Strength and Conditioning, second edition p.404-405
    Baechle, Thomas; Earl, Roger  Human Kinetics, Champaign, IL 2000

"Summer's Back!" - ouch!

As spring passes into summer and the bulk of my client population switches from student athletes to weekend warriors and garden gladiators, so do to the bulk of the "c/o's" from peripheral conditions to back pain, specifically low back pain. Three new cases just last week!

Back Pain is not easy to assess for the therapist or diagnose for the physician, either medical or chiropractic, and can be even harder to explain to the client or patient. This is because there can be, and usually is, more than one factor causing the pain. If there is one dominant factor directly causing the pain, then this is addressed first. Decreasing the major cause of pain allows for greater range of motion which will facilitate the natural healing process of the body as well as allow the therapist to address the imbalance that caused the pain, if this is possible. Sometime the lack of integrity in structures leaves no alternative but surgical intervention. Fortunately, this is usually not the case.

Who do I see about my pain?

If your pain is locally sharp and disabling, it's my duty to refer you out to an orthopedic physician and I recommend that you pursue that course before you see me if those are the symptoms you are experiencing. Be sure your physician is paying close attention to your history and takes the time to perform manual clinical tests on you. MRI's are not enough. In fact, MRI's can present very clear but misleading images. In the case of herniated nucleus pulposus (HNP) they have a 25% false positive rate (1). Where the pain is being referred from and what structures are referring the pain (nerve, ligament, joint or joint capsule) can and should, in my opinion, all be tentatively identified before radiographs are ordered. Medication or injections to decrease inflammation may be options as well as, in severe cases, surgery. Most Physicians will prescribe the most conservative treatment possible.

If your pain is not is not disabling and the pain is local, chiropractic care has been shown to be very effective on acute conditions, especially within the first 6 weeks. A good chiropractor will educate their patient about their condition and provide them with advice about how to prevent the condition from returning, if that is possible.

If physical therapy has been ordered by your physician, it can be the best road to travel toward healing if the patient is compliant. This is because many of the causes of low back pain are due to weaknesses and imbalances that the physical therapist can address. The mantra "Everything heals in the presence of motion" is most relevant in the case of low back pain where inactivity is often one the greatest contributing factors to onset as well as one of the greatest obstacles to healing.

There is much controversy about the role of passive manual therapy, specifically massage therapy, with respect to severe low back pain. For example, in the case of HNP, it has been noted by some that massage is often engaged during the natural healing cycle in which the natural spontaneous re-absorption of the effused nucleus pulposis would have occurred with normal return to movement regardless of the techniques applied. I have to disagree. Is massage is not contraindicated for the pain I would encourage the patient to engage the services of a therapist. Skillfully applied massage will help decrease both inflammation and tension which will facilitate movement, which will in turn aid the natural healing process. Everything heals in the presence of motion - massage therapy can help you regain that motion.

Summer is short! So if you are having back pain, please schedule an assessment with me so we can find the right direction for you to heal the fastest.

References:

1. http://emedicine.medscape.com/article/1263961-overview

References utilized:

Hammer, Warren I. “Functional Soft Tissue Examination and Treatment by Manual Methods, 3rd Edition” Sudbury, MA Jones and Bartlett Publishers, 2007

PRP and Blood Flow Restriction Exercise VS Dynamic Muscular Therapy

Great strides are being made in developing new techniques that allow active people to remain active into the later decades of their life. Research is being conducted on methods of healing injuries to muscle tissue, primarily by manipulating or eliminating scar tissue formation. Unchecked scar tissue formation within muscle tissue after an injury can impede healing and result in weak connective tissue leading to increased probability of re-injury and muscle weakness. Platelet-rich plasma therapy (PRP) shows considerable promise, but much research still needs to be done to understand the exact mechanisms involved to determine the “when, where and how much” for safe effective prescription. Presently, injections are expensive and, without a universal protocol, show mixed results.

Research is also being done on popular methods of rebuilding active muscle tissue, such as blood-flow restriction exercise which tricks the body into believing it needs to boost the protein necessary to build muscle tissue. Although the potential benefit to older active adults would considerable, the safety of this procedure for older adults is still being studied, blood clotting being a major concern.

Fortunately, there is a time proven method for controlling scar tissue formation and maintaining optimal tissue health in active adults and athletes of all ages – sports massage and dynamic muscular therapy. Sports massage during training and competition can prevent the need for medical intervention later and dynamic muscular therapy can resolve many chronic athletic injuries years after they have occurred – without the need of medication, injections or surgery.

Continued research into methods of medical intervention is essential and I believe breakthroughs for those people who need those options are close at hand. However, the most conservative, safest and effective method for maintaining musculotendinous health is still guided exercise reinforced and maintained by manual therapy.



References utilized:

http://www.boston.com/lifestyle/health/articles/2011/02/21/targeting_sports_related_injuries_with_new_treatments/