Advances in surface electromyographic (sEMG) signal decomposition algorithms have allowed for a richer understanding of motor unit behavior during voluntary contractions. However, this technology has primarily been applied to conditions in which muscle length remains constant (isometric contractions) and force is low. It is unclear if previous findings obtained during isometric contractions are applicable to dynamic, real-world movements, particularly when examined across days. We sought to determine the reliability of firing rates from the biceps brachii during the concentric (lifting) and eccentric (lowering) phases of one-repetition maximum (1RM) curls using a novel sEMG signal decomposition algorithm. Fourteen resistance trained adults (six males, eight females) participated in three laboratory visits, during which 1RM strength for the barbell curl exercise was assessed while sEMG signals were recorded from the biceps brachii. The motor unit mean firing rate (pulses per second [pps]) versus action potential amplitude (millivolts [mV]) relationship was quantified, and linear regression was used to determine the slopes and y-intercepts. The slopes during both the concentric and eccentric phases demonstrated intraclass correlation coefficients (model 3,1) ≥ 0.861, standard errors of measurement ~26.5%, and minimal differences needed to be considered real ~34.5 (pps/mV). The y-intercepts displayed intraclass correlation coefficients ≥ 0.375, standard errors of measurement ≥ 10.0%, and minimal differences needed to be considered real ≥ 7.8 (pps). For both the slopes and y-intercepts, there were no significant differences across days (p > .05) and small effect sizes were observed (ƞp2 < 0.01). In summary, motor unit data from the biceps brachii obtained during high-force, dynamic contractions across multiple days appears to demonstrate sufficient reliability to track neuromuscular adaptations.

Muscle strength declines ~3% per year after the age of 70, leading to functional impairments and the loss of independence. Resistance training guidelines for older adults are typically based on free-weight and machine exercises, which may be inaccessible and lack carryover to activities of daily living. The present study tested the hypothesis that resistance training adaptations are task specific in older adults. Thirty older adults (8 males, 22 females; mean age = 71 years) were randomly assigned to participate in 6 weeks of supervised, high-intensity resistance training (twice per week) utilizing free-weight and machine exercises (traditional) versus functional activities that were overloaded with a weighted vest (functional). Participants were thoroughly familiarized with the exercises and testing prior to beginning the study. Major outcome measures included assessments of functional performance, five-repetition maximum strength, isometric knee extensor force, and quadriceps muscle mass and muscle quality. Physical activity and nutrition were monitored. The study results demonstrate that the magnitude of improvement within a given outcome was largely dependent on group assignment, with greater improvements in gait speed and the timed-up-and-go in the functional group, but 2-3x greater five-repetition maximum strength improvements for the trap bar deadlift, leg press, and leg extension exercises following traditional resistance training. Both groups showed improvements in isometric knee extensor force and muscle size, suggesting that some aspects of the observed adaptations were generic, rather than specific. Importantly, accelerometer data revealed an increase of time spent in moderate-to-vigorous activities outside of the laboratory. Overall, these novel findings suggest that, among older adults, 1) resistance training adaptations exhibit a high degree of task specificity and 2) significant improvements in functional outcomes can be achieved with the simple use of a weighted vest.

Ninety percent of all low back pain cases are classified as non-specific low back pain (NSLBP). NSLBP stands as the leading cause of disability and premature retirement worldwide. It is crucial to intervene between the ages of 18-45 years old as NSLBP prevalence increases with age. Providing patients with innovative feasible methods to undertake rehabilitation can enhance their exercise literacy. This 6-week randomized controlled trial evaluated outcomes of pain, disability, adherence, compliance, and lateral abdominal wall muscle thickness between a gamified exercise group and an at-home exercise packet group. Forty participants were allocated into a gamified group or a packet group. Participants completed a 6 week at-home exercise protocol that included the seven core exercises. Weekly hold times were collected with electronic surveys. The gamified group received a leaderboard of the hold times each week. The first visit, 3-week survey, and last visit included questionnaire completion regarding the outcomes. The first and last visit included dynamic ultrasound to measure the lateral abdominal wall during exercise static and starting positions. Disability was significantly lower at 6 weeks compared to baseline in both groups. No significant findings between groups or within groups were found regarding adherence. At 6 weeks, the packet group had a higher % thickness change in the right internal oblique during two exercises compared to the gamified group. The packet group had a higher % thickness change in the left internal oblique during the foot-elevated side plank and dead bug. Disability was significantly decreased in both groups from baseline to 6 weeks. Participants had decreased fear-avoidance beliefs at the end of 6 weeks, suggesting an increased willingness to engage in activity and exercise. The gamified group did not have greater exercise adherence, although they did have 12% higher compliance. Internal oblique % thickness had the greatest change of muscles.

Indiana University-Purdue University Indianapolis (IUPUI) / Cues have been theorized to promote health behaviors but currently our understanding of the effectiveness of cues is inconclusive. The purpose of this systematic review was to assess the effectiveness of cue interventions in promoting physical activity (PA). Six databases were searched which captured 3,996 articles. After comparison with the eligibility criteria, 19 articles were included in the review. Data extraction revealed that while cues were effective in increasing PA behavior, less than half of the studies (n = 8) were supported by theory-based methodologies. We concluded that cue-based interventions are effective for promoting PA behavior, but future research must develop valid measures of cues and incorporate theory into their study designs. The purpose of the thesis study aimed to address this gap by testing if cue consistency would help explain PA habit and behavior through the Dual Process approach. We conducted an observational study with two measurement periods. We recruited 196 participants via an online volunteer registry. Participants completed measures of exercise behavior, intention, habit, perceived behavioral control (PBC), affective attitudes, and cue consistency at baseline and one month later. We ran a Hierarchical Multiple Regression analysis to determine whether a) habit, intention, PBC, affective attitudes, and cue consistency predicted moderate-vigorous physical activity (MVPA) and b) whether PBC, affective attitudes, and cue consistency predicted habit. Our results showed that MVPA was significantly predicted by habit (β = 0.23, p < 0.01), intention (β = 0.16, p < 0.05), PBC (β = 0.23, p < 0.01), affective attitudes (β = 0.20, p < 0.05), and cue consistency (β = -0.20, p < 0.05). Habit was predicted by affective attitudes (β = 0.48, p < 0.001) and cue consistency (β = 0.32, p < 0.001), but PBC (β = 0.10, p = 0.11) was not significant. We found a stronger relationship between cue consistency and habit than previous studies that evaluated cues individually, supporting the cue consistency construct. Our results suggest that cue consistency should be incorporated in the Dual Process approach as a determinant of habit. Future research should look to replicate our findings through cue-based interventions grounded in theory.

Background Field Hockey is an Olympic sport that is played widely across the world at various levels. In South Africa, it is a growing sport with increasing participation for both males and females. It is a high-speed team sport, consisting of short bursts of sprinting with technical coordination of a stick and ball, as well as the tactical execution of a coach's game plan. Participation in sports, including field hockey, comes with an accepted risk of injury; however, within the team setting it can have several implications for the individual: their health, physical performance, and psychological state, both immediately and in the long term. Despite injury incidence in other team sports being well-documented, there is limited research in field hockey generally, and injury incidence and associated risk factors in South African field hockey specifically. Aim The aim of the present study was to determine the incidence of injury and associated factors amongst players participating in the 2018 South African men's and women's inter provincial field hockey tournament. Objectives The specific objectives of the study were to determine (at the 2018 men's and women's senior field hockey seven-day inter provincial tournament in South Africa): • the incidence of injury amongst players; • the burden of acquired sport injuries defined by time loss and medical attention; • the associative factors related to injury (i.e. coaching qualifications, presence of medical staff, and other non-modifiable risk factors); and • the injury incidence, injury burden and distribution of anatomical injuries between males and females. Methods The study had a descriptive, longitudinal design. All players and coaches attending the 2018 South African Hockey Association men's and women's IPT were invited to enrol in the study and were recruited prior to the start of the respective tournament periods. All the attending players participate in senior field hockey, either for club or university teams in their province. Each provincial hockey union selects their best available team of players to represent them at the inter provincial tournament which comprises of three sections. Only the teams participating in the “A” sections were eligible for recruitment into the study. The female tournament was hosted in Durban during May of 2018 and the male tournament was hosted in Pietermaritzburg in August of 2018. Participants were excluded if they were under 18 years of age or did not provide informed consent. Enrolled coaches and players were asked to complete a self-reported questionnaire. Players information was used to gather the provincial team, playing position and previous injury history. Coaching information was used to gather the educational level, years of experience and the resources available to coaches. Players were additionally asked to independently complete daily injury report forms on all seven tournament match days. This was used to collect information on injury incidence and nature, medical attention required, and time loss during the tournament week. Results Two hundred and seventy-two players (133 females; 139 males) and 22 coaches took part in this study. All injury incidence was found to be 99.5 (95% CI: 71.9 – 127.1) injuries per 1000 player match hours for males and 77.9 (95% CI: 47.1 - 108.1) injuries per 1000 player match hours for females. The incidence of medical attention injuries was 70.3 (95% CI: 46.1 – 94.4) injuries per 1000 player match hours for males, and 51.9 (95% CI: 32.3 – 71.5) injuries per 1000 player match hours for females. The incidence of time loss was 7.5 (95% CI: -0.7 – 15.75) injuries per 1000 player match hours for males, and 4.3 (95% CI: 1.04 – 9.7) injuries per 1000 player match hours for females. A large portion of injuries affected the lower extremity, accounting for 69% of injuries in male players and 70% of injuries in female players. There were no significant relationships between injury incidence and the availability of team medical support staff, coaches' education level, coaches South African Hockey Association (SAHA) level, or coaches' first aid qualifications respectively. However, players with coaches who had a Federation of International Hockey (FIH) qualification had lower injury incidence rates compared to players with coaches who did not hold this qualification (p = 0.015; Fisher exact), with a lower incidence of injury in players coached by a FIH qualified coach (logistic regression analysis p = 0.054). Players who reported previous injuries within the last 12 months were 3.5 times more likely to sustain an injury during the tournament, compared to players with no previous injury history (p < 0.0001). Female players were 2.4 times more likely to seek medical attention compared to male players (p = 0.046). There was a statistically significant association between players reporting previous injury (within the past two years) and injury during the tournament (p < 0.0001), with players who had a previous injury being 5 times more likely of sustaining an injury during the tournament. Conclusion To our knowledge, this was the largest observational study conducted in South African field hockey that included both male and female players. High incidence rates of all injuries and medical attention injuries were identified, however, the incidence of time loss injuries was much lower in comparison to existing literature. It is possible that players continue to participate in matches despite injuries requiring medical attention, that medical support staff may not limit match participation for injured players adequately, or that players seek reassurance from medical support staff for minor injuries. The findings support the existing literature reporting that the lower extremity experiences the largest amount of injuries reported by field hockey players. In the present study, the lower extremity was affected in 69% of all injuries reported in the male tournament, and in 70% of all injuries in the female tournament. In addition, previous injury history was identified as a significant risk factor for injury, which is aligned with findings from injury monitoring studies of different team sports. The findings of this study highlight the need for consensus on injury definitions in field hockey. Further research is critical to determine injury prevention strategies for male and female field hockey players.

No description available.

No description available.

No description available.

No description available.

No description available.