Effects of new military footwear on knee loading during running

Military recruits are known to be susceptible to chronic injuries. The knee is the most common injury site and patellofemoral pain has been demonstrated as the leading mechanism for medical military discharge. Military boots have been cited as a key mechanism responsible for the high incidence of chronic injuries. The British Army has therefore introduced two new footwears – a cross-trainer and running shoe to reduce the incidence of chronic injuries. The aim of this study was to compare knee joint kinetics of the cross-trainer and running shoe in relation to conventional military boots. Twelve male participants ran at 4.0 m s−1 in each footwear condition. Knee joint kinetics was obtained and contrasted using repeated-measures ANOVAs. The results showed that patellofemoral load was significantly greater in the military boots. However, peak knee abduction moment was significantly greater in the running shoes. On the basis of the findings from this study, it is recommended that recruits who are susceptible to injuries mediated through excessive knee loads select the cross-trainer for their running activities

Specialist Classroom Teacher Mentoring and Knowledge Generativity: Exploring trust, support, challenge, risk-taking, and confidence.

The Specialist Classroom Teacher (SCT) position involves a mentoring function that is an integral part of mentoring and induction programmes for teacher-mentees in secondary and area schools in New Zealand. SCT-mentor and teacher-mentee relationships should be confidential and high trust relationships and should involve professional growth for each teacher-mentee as an increase in capacity. This small scale qualitative study involves three purposefully selected cases each of which comprises a SCT-mentor working collaboratively with a teacher-mentee. Challenge, for professional growth as generativity of new practice and/or knowledge for the mentee, should be evident within the mentoring relationship. This study begins by examining documentation on the SCT position and how the position relates to mentoring for generativity. A conceptual model provides a focus for the review of the literature because it identifies some of the key concepts initially considered to be central to mentor-mentee interactions. These concepts include trust, support, risk-taking, and challenge, and to these is added confidence because this concept emerged in the data. Primary data is collected from two naturally occurring mentoring meetings involving each SCT-mentor and teacher-mentee only. This data is analysed and used to formulate questions for one semi-structured interview involving the researcher and each participant pair for each case. Participant perceptions of the concepts and concept interactions within each relationship are sought from interpretive and phenomenological approaches within the interviews. Whereas there is a major focus on support as a mentoring function in the literature, this study found that trust is the basis of each mentoring relationship and that trust underpins the generative process. Discussion centres on the relationship between trust and support, and significantly confidence emerged as a concept that leads to risk-taking behaviour. This emergence of confidence necessitated a revision of the conceptual model presented in the conclusion. Some key points in the discussion and conclusion are: appropriate challenge, static and futuristic support, fields of support, reflective dialogue using tools such as parallel conversations , and realisations pertaining to the 'conscious competence learning model'. This study suggests a shift in focus in the literature from support functions of SCT-mentors to trust building functions because trust-based mentoring relationships are more likely to endure, and are more likely to underpin greater risk-taking behaviours. This study questions the notion that 'deepest trust' through value congruence is the deepest form of trust, suggesting that 'acceptance of different values' represents a 'highest form of trust'

The Effects of Barefoot and Shod Running on Limb and Joint Stiffness Characteristics in Recreational Runners.

The authors aimed to determine the effects of barefoot (BF) and several commercially available barefoot-inspired (BFIS) footwear models on limb and joint stiffness characteristics compared with conventional footwear (CF). Fifteen male participants ran over a force platform at 4.0 m.s-1, in BF, BFIS, and CF conditions. Measures of limb and joint stiffness were calculated for each footwear. The results indicate that limb and knee stiffness were greater in BF and minimalist BFIS than in CF. CF and more structured BFIS were associated with a greater ankle stiffness compared with BF and minimalist BFIS. These findings serve to provide further insight into the susceptibility of runners to different injury mechanisms as a function of footwear

Sex differences in limb and joint stiffnes in recreational runners

Purpose. Female runners are known to be at greater risk from chronic running injuries than age-matched males, although the exact mechanisms are often poorly understood. The aim of the current investigation was to determine if female recreational runners exhibit distinct limb and joint stiffness characteristics in relation to their male counterparts. Methods. Fourteen male and fourteen female runners ran over a force platform at 4.0 m · s–1. Lower limb kinematics were collected using an eight-camera optoelectric motion capture system operating at 250 Hz. Measures of limb and joint stiffness were calculated as a function of limb length and joint moments divided by the extent of limb and joint excursion. All stiffness and joint moment parameters were normalized to body mass. Sex differences in normalized limb and knee and ankle joint stiffness were examined statistically using independent samples t tests. Results. The results indicate that normalized limb (male = 0.18 ± 0.07, female = 0.37 ± 0.10 kN · kg · m–1) and knee stiffness (male = 5.59 ± 2.02, female = 7.34 ± 1.78 Nm · kg · rad–1) were significantly greater in female runners. Conclusions. On the basis that normalized knee and limb stiffness were shown to be significantly greater in female runners, the findings from the current investigation may provide further insight into the aetiology of the distinct injury patterns observed between sexes

Agreement Between the Stages Cycling and SRM Powermeter Systems during Field-Based Off-Road Climbing.

The aim of this study was to determine the agreement between two portable cycling powermeters for use doing field based mountain biking. A single participant performed 15 timed ascents of an off-road climbs. The participants bicycle was instrumented with Stages Cycling and SRM powermeters. Mean and peak power output and cadence were recorded at 1 s intervals by both systems. Significant differences were determined using paired t-tests, whilst agreement was determined using 95% ratio limits of agreement (LoA). Significant differences were found between the two systems for mean power output (p<.001), with the Stages powermeter under reporting power by 8 % compared to the SRM. LoA for mean power output were 0.92 ×÷ 1.02 (95% LoA = 0.90 – 0.93). Peak power output was also significantly lower with the Stages powermeter (p=.02) by 5 % when compared to the SRM powermeter. LoA for peak power output were 0.94 ×÷ 1.09 (95% limits of agreement = 0.87 – 1.03). Significant differences were found for mean cadence between the two powermeters (p=.009), with LoA being 0.99 ×÷ 1.01 (95% limits of agreement = 0.99 – 1.00). This study found that though the Stages Cycling powermeter provided a reliable means of recording power output and cadence, the system significantly underestimated mean and peak power output when compared with the SRM system. This may in part be due to differences in strain gauge configuration and the subsequent algorithms used in the calculation of power output and the potential influence of bilateral imbalances within the muscles may have on these calculations

The test-retest reliability of different ankle joint center location techniques

Accurate and reliable joint identification is imperative for the collection of meaningful kinetic and kinematic data. Of the lower kinetic chain both the hip and knee joints have received a considerable amount of attention in 3D modelling. However, the reliability of methods to define the ankle joint center have received very little attention. This study investigated the reliability of the two marker method (TMM) and the functional ankle method (FAM) on estimating the ankle joint center. Furthermore, the effects of the two-marker method reliability for defining the ankle joint center when the ankle was covered with a brace or protector was investigated. 3D kinematic data was collected from ten participants (8 female and 2 male) whilst walking. The ankle joint center was defined twice using each test condition; TMM (WITHOUT), FAM (FUNCTIONAL), TMM when the ankle was covered with a brace (BRACE), and TMM when the ankle was covered with a protector (PROTECTOR). Intraclass correlations (ICC) were utilised to compare test and retest waveforms and paired samples t-tests were used to compare angular parameters. Significant differences were found in the test-retest angular parameters in the transverse and sagittal planes for the WITHOUT, BRACE, and FUNCTIONAL conditions. The strongest test-retest ICC’s were observed in the WITHOUT and PROTECTOR conditions. The findings of the current investigation indicate that there are fewer errors using the TMM when the ankle is uncovered or when covered with soft foam that is easy to palpate through

The IPO market: Do investors and analysts who follow IPOs learn? Working paper series--02-26

5370 IPOs are examined between 1975 and 1996 for evidence of trends in investor and analyst behavior over time. Following Ritter (1991) and Loughran and Ritter (1995), wealth relatives are calculated and aftermarket performance is examined each year over the sample period. IPOs followed by analysts, and reported on IBES within one year of the offer date, have consistently outperformed IPOs not followed by analysts. Historically, however, all firms typically underperform the market in years two and three following the IPO. This underperformance appears to change in the years following 1990 when IPOs followed by analysts outperform an industry control in each of the first three years following the IPO. This suggests analysts may be learning over time. Investors, however, do not appear to be learning. In spite of years of evidence showing that the returns of IPOs underperform the market in the years following the offering, no change in investor behavior is shown in recent years

How well do conventional stock market indicators predict stock market movements? Working paper series--03-02

5370 IPOs are examined between 1975 and 1996 for evidence of trends in investor and analyst behavior over time. Following Ritter (1991) and Loughran and Ritter (1995), wealth relatives are calculated and aftermarket performance is examined each year over the sample period. IPOs followed by analysts, and reported on IBES within one year of the offer date, have consistently outperformed IPOs not followed by analysts. Historically, however, all firms typically underperform the market in years two and three following the IPO. This underperformance appears to change in the years following 1990 when IPOs followed by analysts outperform an industry control in each of the first three years following the IPO. This suggests analysts may be learning over time. Investors, however, do not appear to be learning. In spite of years of evidence showing that the returns of IPOs underperform the market in the years following the offering, no change in investor behavior is shown in recent years

Effect of front and back squat techniques on peak loads experienced by the Achilles tendon

Background A primary technique in the discipline of strength and conditioning the squat has two principal ‘back and front’ variants. Despite the physiological and strength benefits of the squat, the propensity for musculoskeletal injury is high. The current investigation examined the influence of the front and back squat variations on the load experienced by the Achilles tendon. Material/Methods Achilles tendon loads were obtained from eighteen experienced male participants as they completed both back and front squats. Differences between squat conditions were examined using Bonferroni adjusted (p = 0.0125) paired t-tests. Results The results showed that the peak Achilles tendon load was significantly greater in the back squat (2.67 ±0.74 B.W) condition compared to the front squat (2.37 ±0.69 B.W). Conclusions Given the proposed relationship between the magnitude of the load experienced by the Achilles tendon and tendon pathology, the back squat appears to place lifters at greater risk from Achilles tendon injury. Therefore, it may be prudent for lifters who are predisposed to Achilles tendon pathology to utilize the front squat in their training