The Association Between Different Clinical Methods for Evaluating Lower Extremity Muscular Function

Insufficient muscular strength at the hip and thigh may increase an athlete\u27s susceptibility to lower extremity injuries. In an attempt to reduce this risk, researchers have proposed lower limb strength testing within preparticipation physical examinations (PPE) and return-to-play (RTP) evaluations. However, because of cost, mobility, and or set-up time, some methods are not feasible in certain settings. Since methodological approaches between methods can vary, having different contraction modes and testing parameters, substitution of one method for another may not be valid. Therefore, the purpose of this study is three-fold: a) to determine the association between isometric and isokinetic contraction modes assessed at the hip, b) to investigate relationships between parameters of muscular strength, c) to assess the relationships between dynametric muscular strength and measures of functional performance. For experiment one, eight-teen recreationally active individuals were recruited. In this experiment, separate Pearson product moment correlations were used to evaluate peak torque (PT) between modes. This experiment determined that the PT evaluated at the hip demonstrated a strong to very strong positive correlation (r =.50 - .87) between isometric and isokinetic evaluated at 60°/s, with the exception of normalized HE (r = .42) and IR (r = .24). For experiment two and three, 62 recreationally active participants were recruited. In experiment two and three, separate Pearson product-moment correlations were used to determine the association between the variables of interest. Experiment two determined that PT accounted for 78 to 98% of the variance in RTD. However, neither PT nor RTD demonstrated a similar relationship to strength endurance. Finally, experiment three, determined that work performed by participants during triple hop for distance (THD) accounted for more than 50% of the variance in absolute AB, AD, HE, HF, KE, and ER PT. In addition, the work performed during the THD also accounted for more than 50% of the variance in absolute AB and AD RTD. Overall, these three experiments indicate that in PPEs and RTP evaluations where tertiary methods might not be feasible, secondary and primary methods for evaluating muscle function may present a viable option for evaluating an individual\u27s PT and or RTD

The Reliability of Three-Dimensional Inertial Measurement Units in Capturing Lower-Body Joint Kinematics during Single-Leg Landing Tasks

International Journal of Exercise Science 15(1): 1306-1316, 2022. 3-D inertial measurement units (IMUs) have advantages over other types of motion capture systems, as IMUs cannot be obstructed by equipment and gear. Therefore, the purpose of this study was to assess the reliability of IMUs in measuring joint angles at the hip, knee, and ankle during two types of single-leg landings: 1) drop-landing (DL) and 2) leap-landing (LL). Nineteen subjects, both males (n = 9, 21.88 ± 1.64 yrs, 178.36 ± 9.68 cm, 185.68 ± 16.63 kg) and females (n = 11, 22.45 ± 4.32 yrs, 171.57 ± 6.55 cm, 70.95 ± 14.99 kg) participated in this study. Participants performed three trials of both tasks. The DL required the participant to drop onto their dominant leg from a 30 cm box onto force plate. The LL task required participants to leap over a 20 cm hurdle onto the force plate. ICC values and SEM calculations were used to assess the IMU’s reliability. Overall, IMUs displayed fair-to-excellent reliability for both tasks (ICC = 0.442-0.962), aside from ankle inversion (ICC = 0.290) & ankle abduction (ICC = 0.216) at initial ground contact and ankle abduction (ICC = 0.234) at maximum vertical ground reaction force, both during the LL task. IMUs can be a reliable measurement tool for lower extremity motion during dynamic landing, so long as factors related to reliability at the ankle are considered

A Submaximal Field Test of Aerobic Capacity does not Accurately Reflect VO2max in Career Firefighters

International Journal of Exercise Science 15(4): 221-230, 2022. Adequate aerobic capacity is crucial to maintaining firefighter safety. The purpose of this study was to compare predicted VO2max scores from a submaximal and maximal step test. Eighteen career male firefighters from a medium sized urban municipality completed both a submaximal Forestry step test and a maximal laboratory WFI step test. A lack of association (p = .017) and low level of agreement (p = .015) was determined between step test protocols producing a mean bias of ± 5.61 mL.kg-1/min-1 with most scores being overestimated. Use of the Forestry step test to predict true VO2max in firefighters should be used with caution when classifying firefighter fitness

Effects of Sex and Load Carried per Kilogram of Body Mass on Landing Technique

International Journal of Exercise Science 14(1): 633-643, 2021. Sex differences and heavy load carriage may contribute to the high rate of musculoskeletal injury in military recruits, particularly within the female population. Thus, the purposes of this study were to determine if load influenced landing quality differently in females compared to males and if load carried per kg body mass was associated to quality of landing. Twenty-eight participants were recruited for this study (males: n = 14; females: n = 14). Participants were grouped by sex. All twenty-eight participants performed three drop-jumps (DJ) under unloaded and loaded conditions. The loaded condition included a combat helmet, tactical vest, and rucksack (22 kg). Two cameras recorded in the frontal and sagittal directions during the three DJ trials. DJ trials were scored using the LESS. There was no significant difference in LESS difference scores between males and females, t(26) = -1.014, p = 0.320, 95% CI = -2.01 to 0.68. Load carried per kg body mass (rs= 0.401, p = 0.034) was significantly correlated to LESS rank order. The results suggest load does not significantly alter landing quality as measured by the LESS. However, participant body mass and load per kg of body may play a role in a person’s ability to adapt to heavy loads

The Effect of Military Load Carriage on Postural Sway, Forward Trunk Lean, and Pelvic Girdle Motion

International Journal of Exercise Science 10(1): 25-36, 2017. Musculoskeletal injuries are a common occurrence in military service members. It is believed that the load carried by the service member impedes stability and alters back and pelvis kinematics, increasing their susceptibility to musculoskeletal injuries, specifically in the lower extremities. The purpose of this study was to examine the effects of two different loads on postural sway, forward trunk lean, and pelvic girdle motion in United States Army Cadets. Twenty male Army Reserve Officers’ Training Corps Cadets participated in this study. Each participant performed the Modified Clinical Testing of Sensory Interaction (mCTSIB) Protocol and the Unilateral Stance (ULS) Protocol under three different rucksack load conditions (unloaded, 16.0 kg, and 20.5 kg loads). Mean postural sway velocity was recorded along with 2-D kinematics of the trunk in the sagittal plane and the pelvis in the frontal and sagittal planes. External loads of 16.0 kg (p \u3c 0.001) and 20.5 kg (p ≤ 0.003) significantly increased mean sway velocity by 16% to 52% depending on stance and visual condition, but did not produce significant changes in trunk and pelvic kinematics

Differences in Stronger Versus Weaker Firefighters in Selected Measures of Power

International Journal of Exercise Science 15(4): 552-560, 2022. Firefighters are required to perform a wide array of physically demanding job tasks, such as forcible entry, charged hose advances and victim extractions. An adequate level of muscular strength and power are required to successfully perform these tasks. The purpose of this study is to investigate the differences in stronger and weaker firefighters in measures of power. Archived data for twenty-seven (age = 34.3 ± 7.9 yr, body height = 176.3 ± 7.2 cm, body mass = 89.4 ± 15.7 kg) full-time firefighters were analyzed. Participants were placed into one of two groups [i.e., stronger (HIGH) (n = 13) and weaker (LOW) (n = 14)], based on their relative isometric mid-thigh pull (IMTPr) performance. Power measures included counter-movement jump (CMJ) height, and peak anaerobic power in watts (PAPW). Significant mean score differences were not discovered between HIGH and LOW IMTPr groups on any measures of lower-body power. Moderate positive correlations were observed between IMTP and CMJ (r = .519; p = .01). This study identified significant differences in absolute and relative strength between firefighters who were able to lift at least 2.0x their bodyweight versus those who were not. Additionally, absolute strength (as assessed by the IMTP) was significantly and positively correlated to CMJ height when compared to their weaker counterparts. These findings may provide insight into approaches for improving occupational performance and durability through the physical development of firefighters via strength and conditioning programs which focus on developing absolute strength, relative strength, and power

The Relationship between Video Game Playing Habits and Reaction Time in Both Males and Females of Different Age Groups.

The purpose of this study was to determine the relationship between video game playing habits, specifically frequency of video game playing sessions, length of video game playing sessions, and type of video game played, and reaction time (RT) in males and females of different age groups. The population consisted of volunteer participants (N = 28). Participants were asked to answer a questionnaire inquiring about their video game playing habits. After completing the questionnaire participants were tested on a choice reaction time apparatus. A Three-Way ANOVA was used to calculate the level of significance between mean reaction time scores (MRTS) and video game playing habits. The results showed that there was no significant relationship between MRTS and video game playing habits