Nicholas J. Hanson

Frontal plane landing mechanics in high-arched compared with low-arched female athletes.

Objective:To examine ground reaction forces (GRFs); frontal plane hip, knee, and ankle joint angles; and moments in high-arched (HA) and low-arched (LA) athletes during landing. Design:Experimental study. Setting:Controlled research laboratory. Participants:Twenty healthy female recreational athletes (10 HA and 10 LA). Interventions:Athletes performed 5 barefoot drop landings from a height of 30 cm. Main Outcome Measures:Frontal plane ankle, knee, and hip joint angles (in degrees) at initial contact, peak vertical GRF, and peak knee flexion; peak ankle, knee, and hip joint moments in the frontal plane. Results:Vertical GRF profiles were similar between HA and LA athletes (P = 0.78). The HA athletes exhibited significantly smaller peak ankle inversion angles than the LA athletes (P = 0.01) at initial contact. At peak vertical GRF, HA athletes had significantly greater peak knee (P = 0.01) and hip abduction angles than LA athletes (P = 0.02). There were no significant differences between HA and LA athletes in peak joint moments (hip: P = 0.68; knee: P = 0.71; ankle: P = 0.15). Conclusions:These findings demonstrate that foot type is associated with altered landing mechanics, which may underlie lower extremity injuries. The ankle-driven strategy previously reported in female athletes suggests that foot function may have a greater relationship with lower extremity injury than that in male athletes. Future research should address the interaction of foot type and gender during landing tasks.

Landing ground reaction forces in figure skaters and non-skaters

Abstract Researchers and clinicians have suggested that overuse injuries to the lower back and lower extremities of figure skaters may be associated with the repeated high impact forces sustained during jump landings. Our primary aim was to compare the vertical ground reaction forces (GRFs) in freestyle figure skaters (n = 26) and non-skaters (n = 18) for the same barefoot single leg landing on a force plate from a 20 cm platform. Compared with non-skaters, skaters exhibited a significantly greater normalised peak GRF (3.50 ± 0.47 × body weight for skaters vs. 3.13 ± 0.45 × body weight for non-skaters), significantly shorter time to peak GRF (81.21 ± 14.01 ms for skaters vs. 93.81 ± 16.49 ms for non-skaters), and significantly longer time to stabilisation (TTS) of the GRF (2.38 ± 0.07 s for skaters vs. 2.22 ± 0.07 s for non-skaters). Skaters also confined their centre of pressure (CoP) to a significantly smaller mediolateral (M–L) (25%) and anterior–posterior (A–P) (40%) range during the landing phase, with the position of the CoP located in the mid to forefoot region. The narrower and more forward position of the CoP in skaters may at least partially explain the greater peak GRF, shorter time to peak, and longer TTS. Training and/or equipment modification serve as potential targets to decrease peak GRF by distributing it over a longer time period. More comprehensive studies including electromyography and motion capture are needed to fully characterise the unique figure skater landing strategy.

Palm Cooling Does not Improve Running Performance

The aim of this study was to test the efficacy of the BEX Runner palm cooling device during a combination of exercise and environmental heat stress. Twelve subjects completed two randomly ordered time-to-exhaustion runs at 75% VO2max, 30 °C, and 50% relative humidity with and without palm cooling. Time to exhaustion runs started once the warm-up had elicited a core temperature of 37.5 °C. Heart rate, Rating of Perceived Exertion, Feeling Scale, and core temperature were recorded at 2-min intervals during each run. Time to exhaustion was longer in control than treatment (46.7±31.1 vs. 41.3±26.3 min, respectively, p<0.05); however, when warm-up time was included in analysis, there was no difference between trials for total exercise time (52.5±24.2 vs. 54.5±31.4 min, respectively). The rate-of-rise of core temperature was not different between control and treatment (0.047 vs. 0.048 °C · min-1, respectively). The use of the BEX Runner palm cooling device during a run in hot conditions did not eliminate or even attenuate the rise in core temperature. Exercise time in hot conditions did not increase with the use of the palm cooling device and time to exhaustion was reduced.

The Effect of Rocktape on Rating of Perceived Exertion and Cycling Efficiency.

Abstract Miller, MG, Michael, TJ, Nicholson, KS, Petro, RV, Hanson, NJ, and Prater, DR. The effect of rocktape on rating of perceived exertion and cycling efficiency. J Strength Cond Res 29(9): 2608–2612, 2015—The purpose of this study was to investigate the effects of Rocktape (RT), a type of kinesiology tape, on perceived exertion and cycling efficiency. Eighteen recreational cyclists volunteered as subjects for this study. Four experimental conditions were used: (a) 60% V[Combining Dot Above]O2peak with RT, (b) 60% V[Combining Dot Above]O2peak without RT, (c) 80% V[Combining Dot Above]O2peak with RT, and (d) 80% V[Combining Dot Above]O2peak without RT. The Borg rating of perceived exertion (RPE) scale was used to evaluate subjective exertion during the cycling bouts. Overall RPE and leg, arm, and chest RPEs were obtained (RPE-O, RPE-L, RPE-A, and RPE-C, respectively). Gross cycling efficiency was determined by calculating the ratio of the amount of work performed to the energy expended. Repeated-measures analysis of variance was used to investigate the differences between the 2 intensities and 2 tape conditions. There were main effects of intensity (p < 0.001) and tape (p = 0.02) found for the RPE-O, with RPE-C showing similar results for intensity (p < 0.001) and tape (p = 0.02). Similar findings were present for the RPE-C, and main effects of intensity (p < 0.001) and tape (p = 0.02) were discovered. A significant main effect of intensity was found for efficiency (p = 0.03), with the 80% intensity condition showing a greater level of efficiency than the 60% intensity condition. However, the use of RT did not increase gross efficiency (p = 0.61). The main finding in this study was that subjects reported a lower level of exertion overall and at the chest, which may lead to increases in overall performance of these athletes. The use of RT before athletic events should not be discouraged.

The Gas Sampling Interval Effect on V˙O2peak Is Independent of Exercise Protocol

Introduction There is a plethora of gas sampling intervals available during cardiopulmonary exercise testing to measure peak oxygen consumption (V˙O2peak). Different intervals can lead to altered V˙O2peak. Whether differences are affected by the exercise protocol or subject sample is not clear. The purpose of this investigation was to determine whether V˙O2peak differed because of the manipulation of sampling intervals and whether differences were independent of the protocol and subject sample. Methods The first subject sample (24 ± 3 yr; V˙O2peak via 15-breath moving averages: 56.2 ± 6.8 mL·kg−1·min−1) completed the Bruce and the self-paced V˙O2max protocols. The second subject sample (21.9 ± 2.7 yr; V˙O2peak via 15-breath moving averages: 54.2 ± 8.0 mL·kg−1·min−1) completed the Bruce and the modified Astrand protocols. V˙O2peak was identified using five sampling intervals: 15-s block averages, 30-s block averages, 15-breath block averages, 15-breath moving averages, and 30-s block averages aligned to the end of exercise. Differences in V˙O2peak between intervals were determined using repeated-measures ANOVAs. The influence of subject sample on the sampling effect was determined using independent t-tests. Results There was a significant main effect of sampling interval on V˙O2peak (first sample Bruce and self-paced V˙O2max P < 0.001; second sample Bruce and modified Astrand P < 0.05). The difference in V˙O2peak between sampling intervals followed a similar pattern for each protocol and subject sample, with 15-breath moving average presenting the highest V˙O2peak. Conclusions The effect of manipulating gas sampling intervals on V˙O2peak appears to be protocol and sample independent. These findings highlight our recommendation that the clinical and scientific community request and report the sampling interval whenever metabolic data are presented. The standardization of reporting would assist in the comparison of V˙O2peak.

The effect of endpoint knowledge on perceived exertion, affect, and attentional focus during self-paced running.

Abstract Hanson, NJ and Buckworth, J. The effect of endpoint knowledge on perceived exertion, affect, and attentional focus during self-paced running. J Strength Cond Res 29(4): 934–941, 2015—The purpose of this study was to determine the effect of endpoint knowledge on psychophysiological variables. Twenty-two runners (11 men and 11 women) participated in 2 conditions: a run with an unknown endpoint and a run to the same distance with knowledge of the endpoint. Rating of perceived exertion (RPE), affect, heart rate, and attentional focus were assessed during testing. Subjects ran faster when the endpoint was known (p < 0.01) but no differences in RPE, affect, or heart rate between conditions were present (p > 0.05). There were differences in attentional focus between conditions (p = 0.034) and subjects reported more associative thoughts in the known endpoint condition. Cardiorespiratory fitness was a significant predictor of attentional focus in the known endpoint condition. In sum, when the endpoint was known, subjects used more associative strategies as RPE increased, and those with higher fitness levels used more associative strategies overall.

Strengthening the Figure Skater: Considerations for Injury Prevention and Performance

ABSTRACT ATHLETES WHO PARTICIPATE IN VARIOUS FIGURE SKATING DISCIPLINES COULD BENEFIT FROM SPECIFIC STRENGTHENING EXERCISES TARGETING THE TRUNK, HIP, AND LOWER EXTREMITY TO PREVENT INJURY AND ENHANCE PERFORMANCE. PARTICULAR ATTENTION SHOULD BE PLACED ON STRENGTHENING THE TRANSVERSE ABDOMINIS, MULTIFIDUS, AND GLUTEAL MUSCLES FOLLOWED BY BALANCE AND POWER TRAINING. THE EXERCISE PROGRAMS PRESENTED SHOULD ALSO INCREASE POSTURAL CONTROL AND REDUCE THE INCIDENCE OF HIP-RELATED INJURY IN SKATERS. IN ADDITION, THESE EXERCISES CAN BE COMPLETED DURING THE ENTIRE TRAINING YEAR, WITH REDUCED INTENSITY AND VOLUME OF WORK LOWER DURING SPECIFIC COMPETITION PERIODS.