Mark E. Lester

Injury Reduction Effectiveness of Selecting Running Shoes Based on Plantar Shape

Knapik, JJ, Swedler, DI, Grier, TL, Hauret, KG, Bullock, SH, Williams, KW, Darakjy, SS, Lester, ME, Tobler, SK, and Jones, BH. Injury reduction effectiveness of selecting running shoes based on plantar shape. J Strength Cond Res 23(3): 685-697, 2009-Popular running magazines and running shoe companies suggest that imprints of the bottom of the feet (plantar shape) can be used as an indication of the height of the medial longitudinal foot arch and that this can be used to select individually appropriate types of running shoes. This study examined whether or not this selection technique influenced injury risk during United States Army Basic Combat Training (BCT). After foot examinations, BCT recruits in an experimental group (E: n = 1,079 men and 451 women) selected motion control, stability, or cushioned shoes for plantar shapes judged to represent low, medium, or high foot arches, respectively. A control group (C: n = 1,068 men and 464 women) received a stability shoe regardless of plantar shape. Injuries during BCT were determined from outpatient medical records. Other previously known injury risk factors (e.g., age, fitness, and smoking) were obtained from a questionnaire and existing databases. Multivariate Cox regression controlling for other injury risk factors showed little difference in injury risk between the E and C groups among men (risk ratio (E/C) = 1.01; 95% confidence interval = 0.88-1.16; p = 0.87) or women (risk ratio (E/C) = 1.07; 95% confidence interval = 0.91-1.25; p = 0.44). In practical application, this prospective study demonstrated that selecting shoes based on plantar shape had little influence on injury risk in BCT. Thus, if the goal is injury prevention, this selection technique is not necessary in BCT.

Influence of exercise mode and osteogenic index on bone biomarker responses during short-term physical training

Prescribing exercise based on intensity, frequency, and duration of loading may maximize osteogenic responses in bone, but a model of the osteogenic potential of exercise has not been established in humans. In rodents, an osteogenic index (OI) has been used to predict the osteogenic potential of exercise. The current study sought to determine whether aerobic, resistance, or combined aerobic and resistance exercise programs conducted over eight weeks and compared to a control group could produce changes in biochemical markers of bone turnover indicative of bone formation. We further sought to determine whether an OI could be calculated for each of these programs that would reflect observed biochemical changes. We collected serum biomarkers [bone-specific alkaline phosphatase (BAP), osteocalcin, tartrate-resistant acid phosphatase (TRAP), C-terminal telopeptide fragment of type I collagen (CTx), deoxypyridinoline (DPD), 25-hydroxy vitamin D (25(OH)D), and parathyroid hormone (PTH)] in 56 women (20.3+/-1.8 years) before, during and after eight weeks of training. We also measured bone mineral density (BMD) at regional areas of interest using DXA and pQCT. Biomarkers of bone formation (BAP and osteocalcin) increased in the Resistance and Combined groups (p<0.05), while biomarkers of bone resorption (TRAP and DPD) decreased and increased, respectively, after training (p<0.05) in all groups. Small changes in volumetric and areal BMD (p<0.05) were observed in the distal tibia in the Aerobic and Combined groups, respectively. Mean weekly OIs were 16.0+/-1.9, 20.6+/-2.2, and 36.9+/-5.2 for the Resistance, Aerobic, and Combined groups, respectively. The calculated osteogenic potential of our programs did not correlate with the observed changes in biomarkers of bone turnover. The results of the present study demonstrate that participation in an eight week physical training program that incorporates a resistance component by previously inactive young women results in alterations in biomarkers of bone remodeling indicative of increased formation without substantial alterations in markers of resorption.

Physical Fitness and Body Composition After a 9-Month Deployment to Afghanistan

PURPOSE To examine change in physical fitness and body composition after a military deployment to Afghanistan. METHODS One hundred and ten infantry soldiers were measured before and after a 9-month deployment to Afghanistan for Operation Enduring Freedom. Measurements included treadmill peak oxygen uptake (peak VO2), lifting strength, medicine ball put, vertical jump, and body composition estimated via dual-energy x-ray absorptiometry (percent body fat, absolute body fat, fat-free mass, bone mineral content, and bone mineral density). RESULTS There were significant decreases (P < 0.01) in peak VO2 (-4.5%), medicine ball put (-4.9%), body mass (-1.9%), and fat-free mass (-3.5%), whereas percent body fat increased from 17.7% to 19.6%. Lifting strength and vertical jump performance did not change predeployment to postdeployment. CONCLUSIONS Nine months deployment to Afghanistan negatively affected aerobic capacity, upper body power, and body composition. The predeployment to postdeployment changes were not large and unlikely to present a major health or fitness concern. If deployments continue to be extended and time between deployments decreased, the effects may be magnified and further study warranted.

Effects of a 4-Month Recruit Training Program on Markers of Bone Metabolism

UNLABELLED Stress fracture susceptibility results from accelerated bone remodeling after onset of novel exercise and may be reflected in bone turnover changes. It is unknown if the bone turnover response to exercise is different between sexes. PURPOSE To assess disparity between sexes in bone metabolism markers during military recruit training and to evaluate relationships between bone turnover markers and factors that may affect bone metabolism. METHODS Volunteers were age-matched men (n = 58) and women (n = 199), 19 yr old, entering gender-integrated combat training. Blood was collected at 0, 2, and 4 months and anthropometric and fitness measures at 0 and 4 months. Serum was analyzed for biomarkers reflecting bone formation (bone alkaline phosphatase and procollagen I N-terminal peptide), bone resorption (C-telopeptide cross-links of type I collagen and tartrate-resistant acid phosphatase), endocrine regulation (parathyroid hormone, calcium, and 25(OH)D), and inflammation (interleukin 1B, interleukin 6, and tumor necrosis factor alpha). Data were analyzed using ANOVA, correlation, and regression analyses. RESULTS Bone turnover markers were higher in men (P < 0.01) and increased similarly for both sexes from 0 to 2 months (P < 0.01). Independent of gender, VO2max (R = 0.477) and serum calcium (R = 0.252) predicted bone formation activity (bone alkaline phosphatase) at baseline (P < 0.01). Serum calcium and parathyroid hormone decreased (2.0 and 6.4%, respectively) from 0 to 2 months (P < 0.001), returning to baseline at 4 months for both sexes. Men exhibited a decrease in 25(OH)D from 0 to 4 months (P = 0.007). Changes in endocrine regulators were significantly correlated with changes in bone turnover markers. Inflammatory markers did not differ between sexes and did not increase. CONCLUSION Military training increased bone formation and resorption markers in 2 months, suggesting rapid onset of strenuous exercise accelerates bone turnover similarly in men and women. Although bone turnover markers were higher in men than women, bone formation status may be related to aerobic fitness and serum calcium independent of gender and may be affected by small changes in endocrine regulators related to nutrition.

Effect of a 13-Month Deployment to Iraq on Physical Fitness and Body Composition

This investigation evaluated the effects of a 13-month deployment to Iraq on body composition and selected fitness measures. Seventy-three combat arms soldiers were measured pre- and postdeployment. Body composition was assessed by dual X-ray absorptiometry (DXA). Strength was measured by single repetition maximum (1-RM) lifts on bench press and squat. Power was assessed by a bench throw and squat jump. Aerobic endurance was evaluated with a timed 2-mile run. Exercise and injury history were assessed by questionnaire. Upper and lower body strength improved by 7% and 8%, respectively (p < 0.001). Upper body power increased 9% (p < 0.001) and lean mass increased 3% (p < 0.05). In contrast, aerobic performance declined 13% (p < 0.001) and fat mass increased 9% (p < 0.05). Fewer soldiers participated in aerobic exercise or sports during deployment (p < 0.001). Unit commanders should be aware of potential fitness and body composition changes during deployment and develop physical training programs to enhance fitness following deployment.

Effect of Specific Short-Term Physical Training on Fitness Measures in Conditioned Men

Abstract Lester, ME, Sharp, MA, Werling, WC, Walker, LA, Cohen, BS, and Ruediger, TM. Effect of specific short-term physical training on fitness measures in conditioned men. J Strength Cond Res 28(3): 679–688, 2014—Physical training programs that enhance battlefield-related fitness needs have been increasingly advocated as operational demands on the US military have increased, but few studies have evaluated program effectiveness. The purpose of this study was to compare a novel 7-week physical training program with traditional army physical fitness training in improving the selected measures of physical fitness and military task performance. One hundred and eighty subjects performed a 30-m rush wearing a fighting load, a simulated casualty recovery wearing a fighting load, a 1-repetition maximum bench press, a maximum repetition pull-up test, a medicine ball put, a vertical jump, and a T-test agility drill to establish test-retest reliability and normative reference values. One hundred thirty-three subjects were assigned by block randomization to either traditional Army physical training (TT) of calisthenics and running or a novel program (NT) of calisthenics, resistance, aerobic, speed, power, and agility training. The results indicated that between-day reliability was high (intraclass correlation coefficients [ICCs] 3,1; 0.87–0.98) for all measures except for the casualty recovery (ICC 3,1; 0.67). Reliability improved for all the measures that were averaged over 3 trials (ICC 3,3; 0.93–0.95). The NT was superior to TT in improving bench press (8 vs. 3%; p < 0.01), medicine ball put (7 vs. 1%; p < 0.01), 30-m rush times (5 vs. 1%; p < 0.01), and casualty recovery times (17 vs. −15%; p < 0.01). These findings suggest that a short-term physical training program is effective in improving strength, power, and speed among previously conditioned men. Future studies should determine if similar training programs mitigate the injury risk in this population.

Clinical utility of tibial motor and sensory nerve conduction studies with motor recording from the flexor hallucis brevis: a methodological and reliability study

BackgroundStandard tibial motor nerve conduction measures are established with recording from the abductor hallucis. This technique is often technically challenging and clinicians have difficulty interpreting the information particularly in the short segment needed to assess focal tibial nerve entrapment at the medial ankle as occurs in posterior tarsal tunnel syndrome. The flexor hallucis brevis (FHB) has been described as an alternative site for recording tibial nerve function in those with posterior tarsal tunnel syndrome. Normative data has not been established for this technique. This pilot study describes the technique in detail. In addition we provide reference values for medial and lateral plantar orthodromic sensory measures and assessed intrarater reliability for all measures.MethodsEighty healthy female participants took part, and 39 returned for serial testing at 4 time points. Mean values ± SD were recorded for nerve conduction measures, and coefficient of variation as well as intraclass correlation coefficients (ICC) were calculated.ResultsMotor latency, amplitude and velocity values for the FHB were 4.1 ± 0.9 msec, 8.0 ± 3.0 mV and 45.6 ± 3.4 m/s, respectively. Sensory latencies, amplitudes, and velocities, respectively, were 2.8 ± 0.3 msec, 26.7 ± 10.1 μV, and 41.4 ± 3.5 m/s for the medial plantar nerve and 3.2 ± 0.5 msec, 13.3 ± 4.7 μV, and 44.3 ± 4.0 msec for the lateral plantar nerve. All values demonstrated significant ICC values (P ≤ 0.007).ConclusionMotor recording from the FHB provides technically clear waveforms that allow for an improved ability to assess tibial nerve function in the short segments used to assess tarsal tunnel syndrome. The reported means will begin to establish normal values for this technique.