Video Abstract for the ESSR 45.2 article “Joint Loading in Runners Does Not Initiate Knee Osteoarthritis” from author Ross H Miller. Runners do not have a greater prevalence of knee osteoarthritis (OA) than non-runners. The hypothesis that joint loads in running do not cause OA is forwarded. Two mechanisms are proposed: 1) cumulative load, which is surprisingly low in running, is more important for OA risk than peak load, and 2) running conditions cartilage to withstand the mechanical stresses of running.

I’ve recently been using an excellent iPhone app called 7-Minute Workout, which has totally changed my life. Its simple, voice-guided power workouts make it easy to exercise in my bedroom using only my body and some basic props, and the app’s game mechanics help make the experience fun rather than a chore. The best part is that, no matter how busy I am, I always have time for a seven-minute workout. I’m currently rocking a three-month daily workout streak and counting.
Your muscles perform several functions during isotonic exercise. They push, pull, bend and straighten. For instance, when you bend your arm at the elbow to perform a bicep curl, you flex your bicep. When you unbend your arm at the elbow to perform a triceps kickback, you extend your triceps. When you lie on your back and push a weight up from your chest, you extend your pectoral muscles. When you perform a pull up, you flex your back muscles. Muscles that perform opposite functions of the same region (such as biceps and triceps flexing and extending the arm) are called complimentary muscle groups. When performing isotonic exercises, it is important to balance exercises between complimentary muscle groups in order to prevent injury and develop balanced strength throughout your body.
Natalie Jill is a very popular fitness trainer who you will see guest starring on some of the other sites and channels found in this list. Her best videos can be found on her personal fitness blog which shares workouts for weight loss, exercise ball routines, jump rope workouts, booty belt workouts, body weight exercises and more. Natalie also shares great healthy recipes and useful nutrition tips on her site.
Video Abstract for the ESSR 44.3 article Peripheral Blood Flow Regulation in Human Obesity and Metabolic Syndrome from author Jacqueline K. Limberg. Both obesity and metabolic syndrome are important cardiovascular disease risk factors. In this review, we explore the hypothesis that young obese adults and adults with metabolic syndrome exhibit alterations in blood flow regulation that occur before the onset of overt cardiovascular dysfunction.

The beauty of squats is you can do them anywhere—in line at the grocery store or while brushing your teeth—so there’s never an excuse to find those extra 30 seconds. Tone It Up founders Karena Dawn and Katrina Scott say the booty shapin’, leg sculptin’ move is their go-to exercise. “Squats are great for toning your thighs and booty and you can do them without any equipment,” they explain. “Just make sure that your feet are hip-width apart and knees don’t go passed your toes throughout the move. This will help prevent injury.” Bonus: Squats are a great way to combat that desk job that’s flattening your butt. Discover 35 Tips for Every Type of Job for more advice!

You acquire 100 new shares, giving you a total of 160. You simultaneously sell 50 shares of the exercised options to pay the total exercise cost ($2,000 ÷ $40 = 50 shares), leaving you with 110. Additional shares must be sold to pay for broker fees and, if exercising NQSOs, withholding taxes. After the exercise, you might own less than the 110 shares.
My favorites are all free, though you can subscribe for more features to most of them as well. But free works just fine. They’re all available on iOS and Android (except for one). They’re all built around the science-based concept of high-intensity circuit training using body weight, so you don’t need any fancy equipment. I’ve done these in hotel rooms, my office, parks, and even in a quiet corner at the airport waiting to get on a plane.
Typical balance exercises include standing on one foot or walking heel to toe, with your eyes open or closed. The physical therapist may also have you focus on joint flexibility, walking on uneven surfaces, and strengthening leg muscles with exercises such as squats and leg lifts. Get the proper training before attempting any of these exercises at home.
Physical activity is beneficial for young people, who are naturally primed to soak up its rewards. The reality is that the majority of today’s youths, however, fall into one of two camps: Either they are athletes, engaging in one or many sports (as well as auxiliary training such as weightlifting and agility work, which can help create lifelong fitness habits) or they are sedentary.
EMG of the Vastus Lateralis (VL), Rectus Femoris (RF), Vastus Medialis (VM) and Biceps Femoris was recorded with pairs of silver chloride circular (recording diameter of 10 mm) surface electrodes (Swaromed, Nessler Medizintechnik, ref 1066, Innsbruck, Austria) with an interelectrode (center-to-center) distance of 20 mm. Recording sites (belly of each muscle, as distal as possible from the hips when the subject was asked to contract his quadriceps at a knee angle of 10 deg) were then carefully adjusted at the beginning of each testing session (electrode placement was drawn on the skin with permanent marker to ensure reproducibility of the recording site). Low resistance between the two electrodes (< 5 kΩ) was obtained by shaving the skin, and dirt was removed from the skin using alcohol swabs. The reference electrode was attached to the patella of the right knee. Myoelectrical signals were amplified with a bandwidth frequency ranging from 10 Hz to 500 Hz (gain: VL = 500; RF and VM = 1000), digitized on-line at a sampling frequency of 2 kHz using a computer, and stored for analysis with commercially available software (Acqknowledge 4.2 for MP Systems, Biopac Systems Inc., Goleta, USA). Due to the pressure of the thigh on the dynamometer chair, the Biceps Femoris EMG signal quality was impaired (e.g. numerous artefacts, problems with electrodes) and therefore not analyzed.
For this basic strength-training workout, you'll do 1 set of 15 reps of each of the nine exercises listed below, resting briefly between exercises as needed. The workout targets all the muscles in the body, including the chest, shoulders, arms, back, hips, glutes, and thighs. It's short and simple—a great way for beginners to get started with strength training. 
In 1912, John Shields Fairbairn, a leading consultant obstetrician at St Thomas Maternity Hospital, London, started a program to revolutionize the medical approach to child delivery.22 Polden M, Mantle J. Physiotherapy in obstetrics and gynaecology. 2nd ed. Oxford: Butterworth Heinemann; 2004. [Google Scholar] This aimed to replace the 19th century medical practice of heavily medicating women during labor and the common use of force to deliver. To implement his vision of providing pregnant women with education and natural physical health for childbirth and recovery, Fairbairn chose Midwife and Physiotherapist Minnie Randell (1875–1974) to lead the newly founded St Thomas School of Physiotherapy, which served as the project’s education and training center.22,23 Polden M, Mantle J. Physiotherapy in obstetrics and gynaecology. 2nd ed. Oxford: Butterworth Heinemann; 2004.
To shake up your strength workout, replace the everyone-does-'em moves (crunches, etc.) with this fresh routine created by Dixon. Do this series two to three times per week, alternating with cardio days; you'll start to see results in as little as two to three weeks. Each move hits the same major muscle groups as the old standbys, but challenges them more, giving you a stronger, sleeker body in the same amount of time. So it's efficient—in the best way possible.
Starting on the hands and knees, keep a flat back and engage the core. Raise the left leg straight back, stopping when the foot is hip-level and the thigh parallel to the floor. Balance for as long as possible, then raise the bottom right toe off the floor, tightening the butt, back, and abs (try to be graceful here!). Hold for up to 10 seconds, then switch legs.
Okay, this one if for the kids, but grown-ups can do it to too. With animated instructions, catchy music, and all the basics of the other full-body workouts, this is another top choice overall. The exercises include some more advanced moves, like tricep dips with a chair and push-ups with rotation, so it’s a great one to do with your kids.                                    

Stand with feet shoulder-width apart. Lift right leg straight back and up; at same time, hinge at waist and bring hands or fingertips to floor in front of left foot. Bend both knees, bringing right knee behind left knee. Press back up through left foot to return to previous position. Do 15 reps, keeping leg raised, then switch sides and repeat. Do 3 sets.

Stretching helps maintain flexibility. We often overlook that in youth, when our muscles are healthier. But aging leads to a loss of flexibility in the muscles and tendons. Muscles shorten and don't function properly. That increases the risk for muscle cramps and pain, muscle damage, strains, joint pain, and falling, and it also makes it tough to get through daily activities, such as bending down to tie your shoes.

Cross-training means mixing in different workouts and training methods rather than focusing on just one type of workout. Not only does this help create a well-balanced fitness plan, but it can help you reach specific goals, too. For example, if you’re getting ready to run a race, you’ll want to cross-train with strength and yoga workouts, which will complement your running and help improve your performance and decrease the chance of injury by building muscle and increasing flexibility. “If you only include one form of training, you may be holding yourself back from the results you deserve,” says Lefkowith.
Or should I say Chalene JAMS! This is a really fun program. I admit I felt kind of foolish and uncoordinated at first, but now that I know the moves I get in there and sweat up a storm! I like that there are low impact modifications for those of us with back or knee issues that preclude a whole lotta jumping around. I haven't lost any weight doing the program (probably more hormonal and metabolic roadblocks than lack of trying) but I feel better when I do it, so I am not disappointed one bit.
If your immune system is constantly fighting both its internal and external environment, it can be more challenging to live, work and exercise with the greater cognitive dysfunction, headaches, allergies, tender lymph nodes and both joint and muscle pain.  Yes, I do get it. However, I want you to be successful. Living myself with M.E, and lyme co-infections, the right approach is essential to making exercise work for us, not against us. 
A compound exercise is a move that incorporates multiple muscle groups, like lunges, deadlifts, and squats. It may also refer to two moves being strung together, like a bicep curl to a shoulder press. Compound exercises are efficient for increasing overall muscle mass and burning calories (because they require more effort to complete), as opposed to isolation exercises, which focus on working just one muscle group (like a bicep curl).
The plank is a yoga position that is basically a push up at the top of the action; you're suspending your body in a straight line from your toes while holding your body at an incline with your arms pressing straight up from the ground. Better yet, you're squeezing your abdominal muscles while you're holding the position. This works the transverse abdominis, the deepest-lying of the abdominal muscles. Though not visible, strengthening it will enhance your core stability and posture, both of which add to the effect of an upright profile.

The Russian twist is a type of exercise that is used to work the abdomen muscles by performing a twisting motion on the abdomen. This exercise is performed sitting on the floor with knees bent like in a "sit-up" position with the back typically kept off the floor at an angle of 45°. In this position, the extended arms are swung from one side to another in a twisting motion with or without weight.
By 1925, Margaret Morris had already integrated remedial exercises within her newly established dance school, Margaret Morris Movement (MMM). Her philosophy claimed that natural dance moves should be healthy and constructive for the body and mind, rather than the deleterious moves dancers were expected to practice and perform at the time. Morris saw the connections between breathing, stamina, range of motion, posture, health, vitality, and how these freed the body to dance and the mind to be creative.49 Morris M. My life in movement. London: Peter Owen Publishers; 1969. [Google Scholar] This philosophy extended itself to the use of natural dance moves as remedial exercises and a healthy active lifestyle. During 1925 and 1926, Morris presented her method to doctors and midwifes in England, France, and Switzerland, among them the St Thomas team. As a result of this meeting, Morris enrolled to study physiotherapy under Randell and graduated in 1933 with distinction.30 Margaret Morris Movement (MMM) [Internet]. Margaret Morris - Biography. 2015 Aug 30 [cited 2015 Aug 30]. Available from: [Google Scholar] Throughout her decade of collaboration with Randell and the St Thomas Project, Morris continued to educate and run MMM with great appreciation from top-tier dancers, students, and artistic critiques. By 1939, her teachers developed movement education and dance centers in 10 countries, most still active today (Figures 7–9).30 Margaret Morris Movement (MMM) [Internet]. Margaret Morris - Biography. 2015 Aug 30 [cited 2015 Aug 30]. Available from: [Google Scholar]
Exercise duration, HRmax and [La]max are presented in fig 2A, B, and C. Visual inspection of the data led to the conclusion that there is no difference in exercise duration and HRmax between the OTS and the NFO patients. For [La]max, a much lower value was found for the OTS patients in combination with a larger reduction from the first to the second test compared with the NFO patients. However, parametric analysis did not indicate significant differences. The main effect of group gave an F ratio of 2.9 for [La]max and an F ratio <1 for exercise duration and HRmax, showing that almost three times as much variance is explained by the group membership (ie, OTS vs NFO) compared with random factors. In addition, sensitivity for OTS detection with [La]max was high (table 2). With a cutoff of 8 mmol l%#x2212;1, four out of the five OTS patients would have been diagnosed correctly from the first exercise test and four out of the four OTS patients from the second exercise test. Sensitivity for NFO diagnosis was lower, however (table 2). From the first exercise test, a correct diagnostic ratio of two out of four was found, for the second test, two out of three.
The benefits of exercise have been known since antiquity. Dating back to 65 BCE, it was Marcus Cicero, Roman politician and lawyer, who stated: "It is exercise alone that supports the spirits, and keeps the mind in vigor."[143] Exercise was also seen to be valued later in history during the Early Middle Ages as a means of survival by the Germanic peoples of Northern Europe.[144]
"Look for something with a lot of short segments," says Neporent. "This way, you can do a 10-minute set and you're not committed to a longer routine." When you're ready, you can add the segments together and the workout will still flow. DVD technology has made it easier for video exercisers to do short segments or put several together, depending on their ability

In 1912, Alexander claimed that the principles of ‘conscious control’ constitute an unfailing remedy for disease, including the cases of shortening of the spine, an injured arm, and a golfer who is practicing his swing.21 Pilates and Alexander [Internet]. Macy JA. Alexander Technique and the Pilates method of movement re-education: A biomechanical perspective. 2010 Dec 6 [cited 2015 Aug 30]. Available from: [Google Scholar] Alexander was against weightlifting, claiming that their focus on isolating muscles did not address the short- and long-term damage of impaired functional movements: ‘The physical body thus had two existences ... one fiercely active, muscular, dynamic, the other sedentary, nervous, static.’21 Pilates and Alexander [Internet]. Macy JA. Alexander Technique and the Pilates method of movement re-education: A biomechanical perspective. 2010 Dec 6 [cited 2015 Aug 30]. Available from: [Google Scholar] He allied himself with the turn of the 20th century MMB movement emergence:20 Alexander FM. Man's supreme inheritance. London: Methuen; 1910. [Google Scholar]

Given that "Superslow" is long out-of-print and much more research and refinement has occurred since the early 1990's I am hesitant to recommend it to anyone other than hardcore collectors of bodybuilding or exercise related ephemera. Ken Hutchins recently updated the entire Superslow manual and further elaborated on many more topics by publishing "The Renaissance of Exercise: A Vitruvian Adventure Volume I" (2011) which is only available via mail-order and not in retail stores. It doesn't even have an ISBN number inside. But "The Renaissance of Exercise" will give you the majority of chapters from the original SuperSlow technical manual in a much more durable hardcover textbook format. It is 320 pages of no-holds-barred Ken Hutchins simply telling the truth about what he has learned after 35 years spent rigorously studying exercise. Considering current prices of some used copies of "Superslow" for sale here on Amazon you might as well spend the $150 with the folks at RenEx and you'll get _WAY_ more for your money. You can also read some of those chapters/articles for free on the RenEx website or at Hutchins' website called SuperSlow Research Zone.
Jump up ^ Olsen CM (December 2011). "Natural rewards, neuroplasticity, and non-drug addictions". Neuropharmacology. 61 (7): 1109–1122. doi:10.1016/j.neuropharm.2011.03.010. PMC 3139704. PMID 21459101. Similar to environmental enrichment, studies have found that exercise reduces self-administration and relapse to drugs of abuse (Cosgrove et al., 2002; Zlebnik et al., 2010). There is also some evidence that these preclinical findings translate to human populations, as exercise reduces withdrawal symptoms and relapse in abstinent smokers (Daniel et al., 2006; Prochaska et al., 2008), and one drug recovery program has seen success in participants that train for and compete in a marathon as part of the program (Butler, 2005). ... In humans, the role of dopamine signaling in incentive-sensitization processes has recently been highlighted by the observation of a dopamine dysregulation syndrome in some patients taking dopaminergic drugs. This syndrome is characterized by a medication-induced increase in (or compulsive) engagement in non-drug rewards such as gambling, shopping, or sex (Evans et al., 2006; Aiken, 2007; Lader, 2008).
The beneficial effect of exercise on the cardiovascular system is well documented. There is a direct correlation between physical inactivity and cardiovascular mortality, and physical inactivity is an independent risk factor for the development of coronary artery disease. Low levels of physical exercise increase the risk of cardiovascular diseases mortality.[22]
Perhaps one of the best benefits of barre is that it’s fun! It incorporates the use of upbeat music and engaging choreography. When working out is fun and enjoyable, your chances of staying with the program greatly increase. The barre method also offers quick results. Barre helps strengthen and tone your muscles without increasing bulk, and it improves your posture. It also increases cardiovascular endurance and metabolism, which helps to quickly burn calories.

In the realm of fitness, three-month workout programs dominate the landscape. You’ve even seen plenty of them in our magazine over the years. Are they effective? Absolutely. But we’re going to let you in on an interesting secret: It doesn’t necessarily take 8 or 12 weeks to get your feet wet in the gym. Not that you’ll be a seasoned vet after four weeks, but if you can just get that first month under your belt, you’ll get yourself over the proverbial hump, where so many fail and give up, and set the stage for a lifetime of muscle gains.

Raphael AJ. Natural childbirth in twentieth century England; PhD thesis. London: Queen Mary University of London; 2010.  To create the method, Randell, (whose brother Francis William Randell and wife Jessie experienced two failed births in 1907 and 1913)24 Wildings & Thurleys, Cantophers & McConnells [Internet]. Hatches, matches and dispatches only. 2008 Nov 11 [cited 2015 Sep 23]. Available from: [Google Scholar] was inspired by Ling’s philosophy and exercises of preventative medicine.22 Polden M, Mantle J. Physiotherapy in obstetrics and gynaecology. 2nd ed. Oxford: Butterworth Heinemann; 2004. [Google Scholar] Her repertoire included full-body movement exercises in the lying, sitting, and standing positions.25 Randell M. Training for childbirth from a mother's point of view. 4th ed. London: J. & A. Churchill Ltd.; 1949. [Google Scholar] The objectives of the pre-natal exercises were ‘to improve the physical and mental well being of the patient – encourage a cheerful and confident outlook towards her confinement and so to help herself effectively during labour’. Pre-natal training included education, stretching, relaxing, and deep breathing with many free arm movements to improve circulation. The daily home exercises were designed to improve muscle tone, increase flexibility, and control of movement. The post-natal exercises were designed to improve the condition of relaxed muscles, in particular the abdominal muscles, so that the figure is restored to normal after confinement.26 Wellcome Library [Internet]. Rodway H. Training for childbirth - and after (1940). 2015 Sep 24 [cited 2015 Oct 3]. Available from: [Google Scholar] As a reflection of the women’s suffrage movement, Randell encouraged female students to use their knowledge and healthy physical ability to gain self-empowerment and help others to do the same. She encouraged women to teach spouses to perform and to teach the exercises calmly and confidently; to reinforce the teamwork between parents and to be of practical assistance during childbirth.25 Randell M. Training for childbirth from a mother's point of view. 4th ed. London: J. & A. Churchill Ltd.; 1949. [Google Scholar]
The split jerk is a very powerful and fast move. HOW TO DO IT: The bar starts in the front rack position with your feet hip-width apart. Take a big breath to tighten your core, then dip straight down just a few inches to get more power. Next, drive the bar up overhead while splitting your legs into a lunge position. The goal is to get under the bar as fast as possible while driving the bar up overhead. MUSCLES USED: Glutes, quads, hamstrings, calves, core, shoulders, back and triceps.

Matt Sauerhoff, owner of The LIV Method says one of his favorite, fastest and easiest to do on the go moves is the wall squat. “Start with your back against the wall and your heels about a foot off the wall. Bend your knees and slide down the wall until your legs create a 90-degree angle,” he says. “Make sure your knees are aligned over your toes/laces. Press heels into the floor and focus on contracting your abs, pressing lower back into the wall so it’s flat. Hold for 30 seconds.” Combine it with these 30 Fat-Burning Foods and you’ll be melting the fat in no time!

The mental benefits of Pilates include an increase in the ability to focus. It takes a great deal of concentration to coordinate your breath and body position during workouts. In fact, Joseph Pilates often referred to his method as “the thinking man’s exercise” due to the improvement in memory and other cognitive functions that results from doing it. A clear mind also reduces stress levels, which translates to an improvement in your overall health.

In total, 1567 participants (790 women) met the inclusion criteria, fulfilled baseline testing and were randomized 1:1 into an exercise training group or to a control group. The exercise training group was further randomized 1:1 to either MCT or HIIT. Participants in the exercise groups were instructed to fill in exercise logs after each exercise session they performed. Data in the present study is based on the exercise logs from the first year of the intervention. Therefore, only participants in the exercise groups were included in the present study (n = 787). Dropouts in the exercise groups during the first year (n = 123) and those with no exercise logs (n = 46) were excluded. A total of 618 participants (291 women) were included in the analyses (Fig. 1). The study was approved by the Regional Committee for Medical Research Ethics (REK sør-øst B: 2015/945) and all participants gave their written informed consent before participation.
However, our goal is not necessarily to move more weight but to safely and efficiently target your muscles. By dramatically slowing the speed of the movements and ensuring that the weight smoothly changes directions, we virtually eliminate the possibility of injury. Excessive momentum is removed so only the muscles (and not the joints, tendons, or ligaments) are taxed.
Bottom line. Strength training with heavy weights is a better way to target your glutes, but that’s not something most people will do. The program includes low- and high-impact routines, so you don’t need to be extremely fit to start. If you don’t mind doing lots of squats and lunges and you like the idea of dancing your way to fitness, this may be good for you. The Brazil Butt Lift eating plan includes basic recipes with easy variations.
Two moves is better than one, right? You may want to do this move on a mat or a towel for padding. Start in a high plank position with core tight. Lower onto both forearms at the same time, maintaining a tight core and level hips. Now push back up onto hands at the same time to return to starting position. Finish by drawing right knee into chest, then left knee into chest, doing a mountain climber.
All three workout methods provide physical and mental benefits. In fact, the Centers for Disease Control and Prevention (CDC), reports that engaging in aerobic and/or muscle-strengthening activities 3 to 5 times a week for 30 to 60 minutes improves your physical health, mental health and mood. It serves to improve sleep, reduce stress and improve your overall sense of well-being. Exercising regularly can help you live a healthier, happier life.
The best 7-minute workouts on the planet are the ones you’ll actually do. This is what I know for sure after testing out more than 30 of them over the past few months. That and yes, they really do work. Adding in short blasts of high intensity interval (HIIT) training consisting of various strength, cardio, core, and flexibility exercises whenever I have a spare seven minutes in my day, have helped me get stronger, leaner, faster, and to feel better overall.
Tabata Intervals. The great thing about many of these techinques is the time saving aspect, and Tabata Intervals are definitely time savers. Developed by Dr. Izumi Tabata for Olympic athletes, Tabata Protocol is a form of High Intensity Interval Training (HIIT) where 20 seconds of work is coupled with 10 seconds of rest then repeated for 8 total rounds Metabolic profile of high intensity intermittent exercises. Tabata, I., Irisawa, K., Kouzaki, M., et al. Department of Physiology and Biomechanics, National Institute of Fitness and Sports, Kanoya City, Japan. Medicine & Science in Sports & Exercise 1997 Mar;29(3):390-5.. The 20 seconds work/10 seconds rest pattern has been shown to tax both aerobic and anaerobic pathways more — and in less time — than intense exercise with longer rest periods, meaning improved overall cardiovascular fitness. This protocol can be done with running/rowing/swimming, bodyweight exercises, or weighted movements.
Both groups exercised most frequently outdoors in nearby area and in nature (Fig. 5). Additional analyses showed that outdoors was the most frequently reported exercise location in both warmer (April–October) and colder (November–March) months. The MCT group had a significantly higher proportion of sessions outdoors than the HIIT group. Contrary, compared to the MCT group, HIIT had a higher proportion of sessions at a gym, sports facility and at home (Fig. 5).

But too much rest may do more harm than good. Once prescribed almost universally for back pain, illness, and discomfort of all kinds, bed rest has been shown in studies to be associated with loss of strength and endurance, changes in soft tissue, bone loss, joint disease, high blood pressure, and weakening of the cardiovascular system. It’s one reason falls are a danger for people over 80: The resulting injuries may heal, but the health complications from staying in bed for weeks can be irreversible.
Aerobic exercise induces mitochondrial biogenesis and an increased capacity for oxidative phosphorylation in the mitochondria of skeletal muscle, which is one mechanism by which aerobic exercise enhances submaximal endurance performance.[98] [92][99] These effects occur via an exercise-induced increase in the intracellular AMP:ATP ratio, thereby triggering the activation of AMP-activated protein kinase (AMPK) which subsequently phosphorylates peroxisome proliferator-activated receptor gamma coactivator-1α (PGC-1α), the master regulator of mitochondrial biogenesis.[92][99][100]
How was it discovered that there is no such thing as an overall, general, cardiopulmonary fitness? Out of shape college kids were recruited for a study where they trained on a stationary bike for 90 days, but only one leg did the pedaling. Before they started training, their VO2max was tested, first using both legs, then only the left leg, and then just the right leg. (VO2max is a measurement of cardiopulmonary efficiency.) As you might imagine, all three results were the same. Then one leg was worked out for 90 days on the bicycle; the other leg got to continue to be a couch potato. At the end of the 90 days, you could tell by looking which leg had been exercised. Now for the revealing part. When VO2max was tested for the leg that had been trained, its VO2max improved as expected. But what do you think happened when the unexercised leg was tested? Do you think its VO2max also improved along with the other leg, or do your think there was no improvement. It's shocking how many personal trainers and exercise physiologists that I put this question to got it wrong. There was no improvement. Proving that cardiopulmonary efficiency is muscle specific. This means that when you get less winded, and your heart rate no longer rises as much after you've trained to do something, it's not your heart or lungs that accounted for the improvement, it's the muscles involved.