You are here: Home / HPRC Blog
RSS Feed for Physical Fitness


Welcome to the HPRC Blog. We've got lots of information here, from quick tips to in-depth posts about detailed human performance optimization topics.

HPRC Fitness Arena: Physical Fitness

Back in action: Regaining peak fitness

Getting back into shape takes dedication and persistence, and doing so safely and correctly may help prevent injuries.

For whatever reason, sometimes we get off track with our fitness regimens—maybe it was an injury, a move, or just life that intervened. Getting back to a peak level of fitness after time away should be done gradually. Injuries such as tendonitis—which could become a long term issue—can occur as a result of doing too much, too fast. The American College of Sports Medicine (ACSM) recommends increasing duration (minutes of exercise) 5-10 minutes every one or two weeks over the first four to six weeks of an exercise program.

Stress Fracture Prevention: Strengthening the Lower Extremity Muscles

Maintaining strength and flexibility in the lower extremities is one of the many important steps toward decreasing the likelihood of developing the small cracks in a bone commonly known as stress fractures.

There are several risk factors for stress fracture development, but a 2011 article in Medicine and Science in Sports and Exercise found that maintaining adequate muscle strength and flexibility in the hips, legs, knees, ankles, and feet is of great importance, especially for women. Here are some exercises from the American Council on Exercise that can help you build strength and flexibility:

Ankle Flexion

Single Leg Push-off

Forward Hurdle Run

Seated Calf Stretch

Standing Dorsi-Flexion (Calf Stretch)

Supine Hamstrings Stretch

Barbell Calf Raises

Jump and Reach

Agility Ladder: Lateral Shuffle

Alternate Leg Push-off

Barbell Jammers

Before beginning any exercise program, however, make sure to consult with a medical professional, especially if you are more than 45 years old.

The lowdown on stress fractures—and how to prevent them

Stress fractures are chronic injuries that occur most often in the lower extremities. Prevention is key and can be helped through adequate attention to nutrition, training surfaces, and footwear, as well as gradual progression in training.

The American Academy of Orthopaedic Surgeons defines a stress fracture as a tiny crack in a bone that occurs when fatigued muscles lose their ability to absorb shock and then transfer stresses to the bone. Most stress fractures occur in the lower extremities, and more than half occur in the lower leg and foot.

A stress fracture is an overuse—sometimes referred to as chronic—injury, which means that it develops over a long period of time—from weeks to months. According to a 2011 systematic review published in Military Medicine, stress fracture incidence is high among U.S. military recruits, ranging anywhere from 3% for men to 9.2% for women.

Since it can take several weeks or months for a stress fracture to heal, the best approach is to avoid getting one. Here are some tips for prevention:

  1. Apply the progression principle of training—gradually increase your training intensity. Slowly incorporate higher-stress activities such as jumping and interval training into your workout. Setting incremental goals can be helpful in carrying out your training routine in a gradual way. And check out HPRC’s Physical Fitness Resources for more information on training and ways to avoid injury.
  2. Check your footwear and make sure it matches your training. Replace footwear that is old or worn.
  3. Pay attention to the surface where you train, since some are easier on the bones and joints of the lower extremities. For example, it is better to jog on softer surfaces such as rubber track or grass rather than on concrete. Also, it’s better to begin training on a flat surface and then progress to hills.
  4. Monitor your diet, specifically calcium and vitamin D intake, and read the National Institute of Health’s Dietary Supplement Fact Sheet on calcium. To learn more about nutrition take a look at HPRC’s Nutrition Resources.

It is important to recognize a stress fracture and seek medical advice early, as discussed in Clinics in Sports Medicine. The Mayo Clinic provides information on the symptoms of a stress fracture.

New One Shot One Kill materials now available online

New program materials for the One Shot One Kill (OSOK) performance enhancement program are now available on HPRC’s website!

One Shot One Kill: Want to learn how the elite warrior accomplishes optimal performance time after time, under the most challenging conditions? The HPRC now has new program materials for the One Shot One Kill (OSOK) performance enhancement program online for you to use and download—by yourself or with your unit! One Shot One Kill (Integrative Platform version) is a “warrior-centric” performance enhancement program that warriors can set up and manage on their own. OSOK-IP is designed to enhance performance, hardiness, and resilience. By building on the skills that Warfighters already possess, OSOK aims to translate good Warfighter qualities to outstanding ones. OSOK-IP comes in two versions:

OSOK-IP Solo is a step-by-step integrative training plan, with supplemental materials, that enables the individual Warfighter to pursue this method of Total Fitness on his or her own and reach the optimal level of performance in almost all areas of life.

OSOK-IP Train the Trainer enables your unit to train as a group by selecting one member to learn and present OSOK-IP to the rest of the unit. This section of the website has the full curriculum available to download and even customize OSOK-IP content for your own military culture and unit.

We look forward to your feedback, too. Check out OSOK and let us know what you think!

Back in motion: Can swinging a kettlebell improve back and shoulder pain?

Exercises with strength-training equipment known as kettlebells may provide relief from back, shoulder, and neck pain.

Kettlebells have been used in Europe for years in strength training, and now they’ve become a popular workout tool here in the United States too. The benefit of kettlebells is that they provide the user a wider range of motion than dumbbells do. Kettlebell workouts engage multiple muscle groups at once, making them a great option for getting a whole-body workout in a short time.

Interestingly, the January 26 edition of the New York Times Health Section reported on a Danish study that suggests kettlebell exercises are a promising musculoskeletal therapy for low-grade back and neck pain.

The study involved middle-aged women with low-grade back, shoulder, and neck pain who were randomly assigned to either a regular kettlebell workout or a general-exercise control group. The study did not include those with chronic pain.

According to the Times article, at the end of the study, the group that did the kettlebell exercises reported less pain, as well as improved strength in the trunk and core muscles, compared with the control group. Overall, the study showed exercising with kettlebells reduced lower-back pain by 57% and neck and shoulder pain by 46%.

For those with core-muscle instability or weak core muscles, kettlebells can be a great way to strengthen those muscles (back, abdominal, glutes, quads, hamstrings) and improve posture. However, along with exercise it is imperative to stretch the hamstrings, since this tends to be a major contributor to lower back pain or discomfort.

It’s important to start slow when using kettlebells and seek professional guidance. Like any other exercise equipment, if used improperly, kettlebells can cause serious injury, and their swinging motion can be difficult to control.

How dangerous is too much training?

Too much training with not enough down time and less-than-optimum nutrition can lead to “overtraining” needing weeks or even months of recuperation.

Getting in the best shape of your life requires you to push your training regime to the limit. However, without appropriate rest periods and diet, this can lead to serious conditions known as “non-functional overreaching” (NFO) and “overtraining syndrome” (OTS). What occurs is that your performance begins to decline, even though you are training as hard as ever, and you start to feel tired and “stale.” Read HPRC’s Overview “Overtraining—what happens when you do too much” to learn about the serious implications of these conditions for Warfighters.

Working out with babies

An Army base in Germany includes babies in their workouts!

At the U.S. Army Garrison in Kaiserslautern (Germany), the base is trying to find more ways to include families in physical fitness. They are providing classes— called “Binkies and Babes” —that spouses can do with their babies. These classes are great ways for spouses to workout with their young children, socialize with other military families, and get a great individual workout!

Overseas military families can sometimes find it difficult to both exercise and manage child care. This is one way overseas bases are moving towards Total Family Fitness. Renee Champagne, the Fitness Coordinator for the Army bases in Germany (and a military spouse herself), sees how “working out and staying physically fit may help a spouse cope during a deployment… which in turn could provide peace of mind to the military member downrange.”

For more information, see the article and video on Stars and Stripes.

Add stretching to your fitness warm-up

Although the value of stretching prior to physical exercise is still in question, the consensus seems to be that it is a good idea to include some—done correctly.

The scientific jury is still out on whether stretching prior to vigorous activity really helps prevent training-related injuries, but the scales tip in favor of doing some as part of your warm-up, just in case. HPRC has just added an in-depth review of the research literature and now offers information to help you decide the best way for you to incorporate stretching into your own fitness program. Check our our new Question from the Field, “Stretching during warm-up,” which also offers a link to even more detailed information.

Runners’ trots

There’s a phenomenon runners sometimes experience that’s commonly called “runners’ trots” – otherwise known as diarrhea – that has risk factors and that can possibly be avoided. Although the “trots” usually don’t last long and are generally nothing to worry about, they certainly can be a major annoyance, causing lost time in training or competition and even embarrassment if there is literally “nowhere to go.”

The most common risk factors cited are for those who are young, female, susceptible to irritable bowel syndrome, or lactose intolerant, as well as those who have had a previous abdominal surgery. The things we do to our bodies that reportedly increase risk are high-intensity exercise, dehydration, vertical-impact sports (e.g., running vs. biking), poor conditioning, medication, and diet. Although these are stated in the medical literature as risk factors, a recent study published in the International Sportmed Journal examined the evidence behind each of these risks to see if they hold up under scrutiny – and there’s surprisingly little evidence to support many of the statements about risk factors for developing “runners’ trots.” Most of the evidence was limited and relied on either single studies or multiple studies with varying results but a tendency toward supporting the conclusion.

Here are the conclusions of this evidence-based study:

The only strongly supported evidence was for dehydration to increase the risk of diarrhea. Female gender, younger age, high-intensity training, vertical impact, and medication had limited support and could go either way. Finally irritable bowel, lactose intolerance, previous abdominal surgery, poor conditioning, and dietary factors had very weak support. Keep in mind that little or no evidence does not make something true or false; it just means we have insufficient scientific evidence for any assumption.

So, based on the studies, how can you avoid “runners’ trots?”

  1. The evidence certainly supports staying well hydrated so that the bowel gets an adequate blood supply.

Even though the evidence for doing some things is not strong, they make sense and are not harmful. These include:

  1. Avoid a large meal 3-6 hours prior to running.
  2. Avoid food or drinks that have non-absorbable sweeteners (such as sorbital or sucralose), caffeine, and/or a high fat content.
  3. Don’t ingest concentrated carbohydrates (high glycemic index) before running.
  4. Be aware that energy bars and gels may contribute to the “trots” for some people.
  5. Avoid taking anti-diarrheal medications such as loperamide (e.g., Imodium) or Lomotil, since they can affect the ability of the body to tolerate heat.
  6. Wear loose-fitting clothing to reduce irritation.
  7. If symptoms persist for more than a few days, seek medical attention to be sure there is not an underlying cause.

    Enjoy your run!

    Announcing Family Physical Fitness on HPRC

    HPRC's Family & Relationships section has a new area on family physical fitness. See what it has for you and your family!

    Warfighters have specific physical activity requirements, but their spouses, children, parents, and other loved ones also have physical fitness requirements for their own individual and family missions. HPRC's family section has a new area that summarizes recent guidelines for physical activity for U.S. adults, and children, and identifies military resources, interactive tools, and exercise workouts and videos. Check it out here!

    RSS Feed for Physical Fitness