Research Round Up

By Charles Bausman

Effect of Energy Beverage Consumption on Pistol Aiming Steadiness in Law Enforcement Officers
Monaghan, Taylor P.; Jacobson, Bert H.; Sellers, John H.; 
Journal of Strength & Conditioning Research . 31(9):2557-2561, September 2017.

“Oklahmoa State University and the U.S. Army Research Institute of Environmental Medicine worked together to study the implications of commercially available Energy Shots and Energy Drinks on pistol marksmanship. Previous studies have “shown that caffeine may provide enhancements in both anaerobic and aerobic exercises. Also, consumption of caffeine may increase cognitive performance in sleep-deprived individuals and in tactical situations, caffeine reduces friend-foe identification errors and decreases time in target detection exercises.

According to the article, previous studies have “shown that caffeine may provide enhancements in both anaerobic and aerobic exercises. Also, consumption of caffeine may increase cognitive performance in sleep-deprived individuals and in tactical situations, caffeine reduces friend-foe identification errors and decreases time in target detection exercises.”

However, other studies showed that caffeine consumption can reduce fine motor skills, a critical component of pistol marksmanship. The study analyzed 10 police officers with laser-practice pistols (no live fire) in order to ascertain marksmanship, comparing those who had consumed energy shots against the control group.”

“The ES group demonstrated significant (p ≤ 0.05) within group pre-to-posttest detrimental effect in the arm-hand aim steadiness after consumption of the ES. In addition, the ES group was significantly less stable in the arm-hand aim steadiness than the placebo group after ES consumption, illustrating the detrimental effect on steadiness resulting from ED consumption.

Energy shots may reduce marksmanship. It is not stated if this is due to the caffeine consumption, the “energy mix” found in energy shots, or the combination of both.

A Review of the Biomechanical Differences Between the High-Bar and Low-Bar Back-Squat
Glassbrook, Daniel J.1; Helms, Eric R.1; Brown, Scott R.1; Storey, Adam G.1,2
Journal of Strength & Conditioning Research: September 2017 – Volume 31 – Issue 9 – p 2618–2634

Researchers at the Sports Performance Research Institute New Zealand examined the mechanical and practical differences and applications of the High Bar Back Squat (HBBS), and the Low Bar Back Squat (LBBS).

“During the traditional HBBS, the bar is placed across the top of the trapezius just below the spinous process of the C7 vertebra. Conversely, during the LBBS, the bar is placed on the lower trapezius just over the posterior deltoid, along the spine of the scapula…the LBBS may result in an ability to lift greater loads in comparison to the High Bar Back Squat. Differences in bar position between the HBBS and LBBS result in an altered center of mass. Therefore, different movement strategies are used to ensure that the center of mass remains within the base of support to maintain balance during the execution of these lifts, which will be covered in this review. These movement strategies manifest as differences in joint angles of the lower-body kinetic chain, vertical ground reaction forces (Fv), and the activity of key muscles.

The LBBS is presented with a greater forward lean and reduced knee flexion (i.e., reduced depth). This results in greater posterior displacement of the hip, and a maximization of the associated force-producing ability. Such displacement of the hip engages the stronger posterior hip musculature (i.e., gluteal, hamstring and spinal erector muscle groups), as supported in this review though analysis of muscle activity studies on each back-squat variation. By contrast, the HBBS presents with greater activation of the anterior thigh musculature (i.e., quadriceps)”

Training to improve Olympic lifts? Use the High Bar Back Squat. Training to improve maximal strength and/or field related performance? Use the Low Bar Back Squat.

Associations of fats and carbohydrate intake with cardiovascular disease and mortality in 18 countries from five continents (PURE): a prospective cohort study
Dehghan, MahshidDiaz, R et al. The Lancet

“The relationship between macronutrients and cardiovascular disease and mortality is controversial. Most available data are from European and North American populations where nutrition excess is more likely, so their applicability to other populations is unclear.

Dietary intake of 135 335 individuals (from across 18 nations, age ranging 35-70 years) was recorded using validated food frequency questionnaires. The primary outcomes were total mortality and major cardiovascular events (fatal cardiovascular disease, non-fatal myocardial infarction, stroke, and heart failure). Secondary outcomes were all myocardial infarctions, stroke, cardiovascular disease mortality, and non-cardiovascular disease mortality. Participants were categorised into quintiles of nutrient intake (carbohydrate, fats, and protein) based on percentage of energy provided by nutrients. We assessed the associations between consumption of carbohydrate, total fat, and each type of fat with cardiovascular disease and total mortality. We calculated hazard ratios (HRs) using a multivariable Cox frailty model with random intercepts to account for centre clustering.”

“High carbohydrate intake was associated with higher risk of total mortality, whereas total fat and individual types of fat were related to lower total mortality. Total fat and types of fat were not associated with cardiovascular disease, myocardial infarction, or cardiovascular disease mortality, whereas saturated fat had an inverse association with stroke. Global dietary guidelines should be reconsidered in light of these findings.”

Dietary guidelines often prescribe a higher carb intake with low fats. This would appear to be less effective for long term health and life span in comparison to higher fat diets.

The Relationship of Heart Rate and Lactate to Cumulative Muscle Fatigue During Recreational Alpine Skiing
Seifert, John; Kröll, Josef; Müller, Erich
Journal of Strength & Conditioning Research: May 2009 – Volume 23 – Issue 3 – pp 698-704
“Common indices of fatigue may not respond similarly between downhill skiing and other activities because of the influence of factors such as snow conditions, changing terrain, and skiing style.
The purpose of this study was to investigate the relationship and predictors of common fatigue indices during downhill skiing. Ten healthy female recreational skiers skied for 3 hours under standardized conditions. Feedback on heart rate (HR) and finishing time were given to each skier at the end of each run to maintain a relatively stable load. A chronic stress score (Cstress) was calculated from creatine kinase (CK), cortisol, and isometric endurance.Finishing times and HR from runs 2, 12, and 24 were similar.
Heart rate averaged 82% of HRmax. Heart rate was an insignificant predictor (p = .65) and was poorly correlated (r = 0.16) to Cstress. Blood lactate (LA) was a significant predictor of the Cstress (p = 0.05; r = 0.62). Pre- to postskiing peak forces were not different (p = 0.62), but skiers experienced a significant decrease in isometric endurance from 106.1 ± 29.6 to 93.2 ± 24.0 seconds. Endurance decreased by 13%, whereas cortisol and CK increased by 16 and 42%, respectively. Isometric contraction endurance and blood LA were significant predictors of overall stress. Individual compensation mechanisms and skiing style contributed to highly variable responses during skiing.”
“Whereas HR may indicate stress within a given run, it is not a significant indicator of Cstress and fatigue during recreational alpine skiing. However, the cumulative stress variables and LA can be used in field testing of skiers. It is suggested that LA is a practical on-hill marker of chronic stress.”
The major contribution to endurance during downhill skiing is the heavy eccentric and isometric muscular demand which leads to increased levels increased of blood lactate, reducing performance. Aerobic conditioning does not appear to play a particularly important role in ski performance.  Muscular endurance specific to the eccentric and isometric demands are significant and should be trained prior to ski season.

Differences in Climbing-Specific Strength Between Boulder and Lead Rock Climbers
Fanchini, Maurizio1; Violette, Frédéric2; Impellizzeri, Franco M.1,3; Maffiuletti, Nicola A.2,3
Journal of Strength & Conditioning Research: February 2013 – Volume 27 – Issue 2 – p 310–314
“The purpose of this study was to compare maximal muscle strength and rapid force capacity of finger flexors between boulder and lead climbers of national-international level. Ten boulder (mean ± SD, age 27 ± 8 years) and 10 lead climbers (age 27 ± 6 years) volunteered for the study.
Ten nonclimbers (age 25 ± 4 years) were also tested. Isometric maximal voluntary contraction (MVC) force and rate of force development (RFD) produced in “crimp” and “open-crimp” hand positions were evaluated on an instrumented hold. Climbers were stronger than nonclimbers. More interestingly, MVC force and RFD were significantly greater in boulder compared with lead climbers (p < 0.05), in both crimp and open-crimp positions.”
“The RFD was the most discriminatory outcome, as the largest difference between boulder and lead climbers (34–38%) was observed for this variable. The RFD may reflect the specific requirements of bouldering and seems to be more appropriate than pure maximal strength for investigating muscle function in rock climbers.”
Lead climbers on big walls have less power requirements than boulder climbers in respect to hand/finger strength. Those athletes who focus on bouldering problems should likely train power moves more frequently, while lead climbers have a broader spectrum of fitness training requirements.