What Causes Muscle Cramps in Marathoners?
The runner’s bane is muscle cramps, those painful, activity-stopping pains in side of the ribcage that come from nowhere. Even 70 years after the jogging craze hit, we’re still not sure why these happen. Years ago, one study tested the idea that it was fluid in the stomach itself that was tugging on the omentum, the suspension system for the organs. Other studies have determined that they’re not due to dehydration or electrolyte imbalance. More recently, the “altered neuromuscular control theory” (ANCT) hypothesized that “excessive demand according to their current state of training [generates] an alteration in neuromuscular control.”
A study from Spain tested the hypothesis that cramps are from dehydration and electrolyte depletion combined vs muscle damage. They looked at 64 runners who finished a marathon without cramping and compared them to the 20 finishers who did. They hypothesized that crampers had greater concentrations of muscle damage markers but no differences in dehydration or electrolyte losses.
Since they had data on their cardiovascular capacities, they could estimate the intensities at which each one ran to see if that might impact cramping likelihood.
They found that crampers did not lose more body weight and were no more dehydrated or in electrolyte imbalance. They did, however, have higher markers of muscle damage immediately and 24 hours after the race, leading to the conclusion that crampers “subjected their muscles to an excessive intensity demand in relation to their fitness level,” supporting the ANCT. This suggested that one’s training was linked to the risk of developing cramps during the race. The authors also suggested that strength training would likely help runners, especially those prone to cramping.
JSCR June 2022
Resistance Training Boosts Longevity, Too
Most health and wellness studies and experts tout the benefits of aerobic, or cardiovascular, exercise for reducing morbidities such as heart disease, metabolic disorders, and many cancers. These benefits are a result of making the heart pump large volumes of blood through the vascular system, taking oxygen from the lungs to the large muscles in rhythmic and long-duration movements such as walking, jogging, cycling and swimming. But resistance, or strength, training (RT) offers very similar benefits for older adults even though it does not do what cardio exercise does, as we’ve discussed here, here, and here.
A study from the British Journal of Sports Medicine (Sept. 2022) found that regular RT, in fact, does reduce “all-cause and cardiovascular mortality, with the strongest effects observed when the two types of exercise are combined.” Nonetheless, RT alone is pretty potent: while those who did both types of exercise had around a 40% lower risk of death during the 9-year study compared to those who did neither, those who only lifted had a 9% lower risk.
The combo training benefited women more than it did men, maybe because males tend to have more physically demanding jobs or chores.
The authors hypothesize that RT favorably affects body composition. During RT, muscles have to “redirect more blood flow..the heart is pumping harder, the lungs breathe more” etc. The social aspect, of training in a gym environment, might also help older adults in ways that the physical activity doesn’t account for.
Medscape Oct. 2022
A study in MSSE (Oct. 2022) “examined the effect of acute resistance exercise on GI (gastrointestinal) symptomology, damage and permeability in resistance-trained individuals.” It found that 70% of lifters reported at least one GI symptom after an experimental hypertrophy-style training session, with nausea leading the pack and vomiting coming in a distant second. Males tended to have “the greatest increases in markers of GI damage.”
Get your sleeping habits under control. An article in Sleep (July 2022) showed that those who developed “probable insomnia disorder” (PID) within 3 years of the start of the study demonstrated “self-reported memory worsening [that was] one-and-a-half times greater than for those who developed insomnia symptoms only” or who did not have insomnia. Only those reporting difficulties with sleep onset or maintenance more than 3/wk and said this “significantly interfered with their daily function” were classified as having PID. It seems that worsening sleep patterns may precede cognitive decline. Medscape Sept. 2022
A Japanese study tested whether the benefits to low-load volume to failure (LVoF), low-load to velocity failure (LVeF), and high-load (HL) resistance training were different. All training consisted of 3 sets to each group’s respective end points: volitional fatigue, velocity fatigue (unable to sustain the designated speed of movement), and 80% of 1RM in the LVoF, LVeF, and HL, respectively. Muscle strength, hypertrophy, endurance and power were pre- and post-tested. LVoF and LVeF demonstrated similar levels of acute muscle swelling, blood lactate, chronic hypertrophy, and strength gain. The HL group had greater strength gains overall whereas the LVoF and LVeF had greater muscle endurance and hypertrophy gains. Last month’s REAL News reviewed studies in older women showing similar results. JSCR June 2022