Effect of Aging on Movement Quality in Australian Urban Firefighters.

ABSTRACT: Redshaw, AS, Carrick-Ranson, G, Bennett, H, Norton, KI, and Walker, A. Effect of aging on movement quality in Australian urban firefighters. J Strength Cond Res 37(11): e601-e608, 2023-Adequate levels of movement quality (MQ) are required to safely perform occupational tasks in physically demanding and hazardous professions such as firefighting. Although it is well established that MQ deteriorates with age in population studies, there is conflicting evidence in older tactical populations. This study sought to examine the relationship between age and MQ in Australian urban firefighters. The impact of physical activity, injury history, and body mass index on MQ were also explored. The MQ of 324 professional Australian urban firefighters was assessed using MovementSCREEN MQ assessment tool. Scores of whole-body MQ ranged from 35.3 to 82.6 (0-100 scale), with a mean score of 59.2 ± 10.0. There was a moderate, negative association between MQ and age (r = -0.500; p ≤ 0.001), with those older than 50 years of age having significantly lower scores of MQ than their younger counterparts (p ≤ 0.001). Secondary analysis found that higher body mass index (r = -0.285; p ≤ 0.001), lower habitual physical activity levels (r = 0.165; p ≤ 0.003), and the presence of any musculoskeletal injury in the previous 12 months (p = 0.016) had significant negative effects on composite MQ. Firefighters older than 50, obese, and engaging in low levels of physical activity should be considered a high priority for functional strength training interventions to maintain adequate MQ throughout their careers.

Validating an Adjustment to the Intermittent Critical Power Model for Elite Cyclists-Modeling W' Balance During World Cup Team Pursuit Performances.

PURPOSE: Modeling intermittent work capacity is an exciting development to the critical power model with many possible applications across elite sport. With the Skiba 2 model validated using subelite participants, an adjustment to the model's recovery rate has been proposed for use in elite cyclists (Bartram adjustment). The team pursuit provides an intermittent supramaximal event with which to validate the modeling of W' in this population. METHODS: Team pursuit data of 6 elite cyclists competing for Australia at a Track World Cup were solved for end W' values using both the Skiba 2 model and the Bartram adjustment. Each model's success was evaluated by its ability to approximate end W' values of 0 kJ, as well as a count of races modeled to within a predetermined error threshold of ±1.840 kJ. RESULTS: On average, using the Skiba 2 model found end W' values different from zero (P = .007; mean ± 95% confidence limit, -2.7 ± 2.0 kJ), with 3 out of 8 cases ending within the predetermined error threshold. Using the Bartram adjustment on average resulted in end W' values that were not different from zero (P = .626; mean ± 95% confidence limit, 0.5 ± 2.5 kJ), with 4 out of 8 cases falling within the predetermined error threshold. CONCLUSIONS: On average, the Bartram adjustment was an improvement to modeling intermittent work capacity in elite cyclists, with the Skiba 2 model underestimating the rate of W' recovery. In the specific context of modeling team pursuit races, all models were too variable for effective use; hence, individual recovery rates should be explored beyond population-specific rates.

Evolution of Physical Demands of Australian Football League Matches from 2005 to 2017: A Systematic Review and Meta-Regression.

BACKGROUND: There is extensive research investigating the match demands of players in the Australian Football League (AFL). OBJECTIVE: This systematic literature review and meta-regression sought to analyse the evolution of in-game demands in AFL matches from 2005 to 2017, focusing on the relationship between volume and intensity. METHODS: A systematic search of Ovid MEDLINE, Embase, Emcare, Scopus, SPORTDiscus, and Cochrane Library databases was conducted. Included studies examined the physical demands of AFL matches utilising global positioning system (GPS) technology. Meta-regression analysed the shift in reported volume (total distance and total match time) and intensity (metres per minute [m.min-1], sprint duration and acceleration) metrics for overall changes, across quarters and positional groups (forwards, nomadics and defenders) from 2005 to 2017 inclusive and for each year between 2005 and 2007, 2007 and 2010, 2010 and 2012, and 2012 and 2015/2017 breakpoints. RESULTS: Distance (p = 0.094), m.min-1 (p = 0.494), match time (p = 0.591), time over 18 km·h-1 (p = 0.271), and number of accelerations greater than 4 km·h-1 (p = 0.498) and 10 km·h-1 (p = 0.335) in 1 s did not change from 2005 to 2017. From 2005 to 2007 volume decreased (- 6.10 min of match time; p = 0.010) and intensity increased (6.8 m.min-1 increase; p = 0.023). Volume and intensity increased from 2007 to 2010, evidenced by increases in total distance (302 m; p = 0.039), time over 18 km·h-1 (0.31 min; p = 0.005), and number of accelerations greater than 4 km·h-1 (41.1; p = 0.004) and 10 km·h-1 (3.6; p = 0.005) in 1 s. From 2010 to 2012, intensity decreased, evidenced by reductions in metres per minute (- 4.3; p = 0.022), time over 18 km·h-1 (- 0.93 min; p < 0.001), and number of accelerations greater than 4 km·h-1 (- 104.4; p < 0.001) and 10 km·h-1 (- 8.3; p < 0.001) in 1 s, whilst volume stabilised with no changes in distance (p = 0.068) and match time (p = 0.443). From 2012 to 2015/2017 volume remained stable and intensity increased with time over 18 km·h-1 (0.27 min; p = 0.008) and number of accelerations greater than 4 km·h-1 (31.6; p = 0.016) in 1 s increasing. CONCLUSIONS: Changes in volume and intensity of AFL match demands are defined by discrete periods from 2007 to 2010 and 2010 to 2012. The interaction of rule and interpretation changes and coaching strategies play a major role in these evolutionary changes. In turn, modified game styles impact player game demands, training, and selection priorities. Standardisation and uniformity of GPS data reporting is recommended due to inconsistencies in the literature.

Temporal Trends in the Cardiorespiratory Fitness of 2,525,827 Adults Between 1967 and 2016: A Systematic Review.

OBJECTIVE: To estimate international and national temporal trends in the cardiorespiratory fitness (CRF) of adults, and to examine relationships between trends in CRF and trends in health-related, socioeconomic, and environmental indicators. METHODS: Data were obtained from a systematic search of studies that explicitly reported temporal trends in the CRF of apparently healthy adults aged 18-59 years. Sample-weighted temporal trends were estimated using best-fitting regression models relating the year of testing to mean CRF. Post-stratified population-weighted mean changes in percent and standardized CRF were estimated. Pearson's correlations were used to describe associations between linear trends in CRF and linear trends in health-related, socioeconomic, and environmental indicators. RESULTS: 2,525,827 adults representing eight high- and upper-middle-income countries between 1967 and 2016 collectively showed a moderate decline of 7.7% (95% CI - 8.4 to - 7.0) or 1.6% per decade (95% CI - 1.7 to - 1.5). Internationally, CRF improved in the 1960s and 1970s, and progressively declined at an increasing rate thereafter. Declines were larger for men than for women, and for young adults (< 40 years) than for middle-aged adults (≥ 40 years). All countries experienced declines in CRF with a very strong negative correlation between CRF trends and obesity trends. CONCLUSIONS: There has been a meaningful decline in the CRF of adults since 1980, which has progressively increased in magnitude over time, suggestive of a corresponding decline in population health. Continuous national and international surveillance systems are needed in order to monitor health and fitness trends, especially among low- and middle-income countries for which data do not currently exist. PROSPERO registration number: CRD42013003678.

Accuracy of W' Recovery Kinetics in High Performance Cyclists-Modeling Intermittent Work Capacity.

PURPOSE: With knowledge of an individual's critical power and W', the SKIBA 2 model provides a framework with which to track W' balance during intermittent high-intensity work bouts. There are fears that the time constant controlling the recovery rate of W' (τW') may require refinement to enable effective use in an elite population. METHODS: Four elite endurance cyclists completed an array of intermittent exercise protocols to volitional exhaustion. Each protocol lasted approximately 3.5-6 min and featured a range of recovery intensities, set in relation to the athlete's critical power (DCP). Using the framework of the SKIBA 2 model, the τW' values were modified for each protocol to achieve an accurate W' at volitional exhaustion. Modified τW' values were compared with equivalent SKIBA 2 τW' values to assess the difference in recovery rates for this population. Plotting modified τW' values against DCP showed the adjusted relationship between work rate and recovery rate. RESULTS: Comparing modified τW' values against the SKIBA 2 τW' values showed a negative bias of 112 (46) s (mean ± 95% confidence limits), suggesting that athletes recovered W' faster than predicted by SKIBA 2 (P = .0001). The modified τW'-DCP relationship was best described by a power function: τW' = 2287.2 × DCP-0.688 (R2 = .433). CONCLUSIONS: The current SKIBA 2 model is not appropriate for use in elite cyclists, as it underpredicts the recovery rate of W'. The modified τW' equation presented will require validation but appears more appropriate for high-performance athletes. Individual τW' relationships may be necessary to maximize the model's validity.

Predicting Critical Power in Elite Cyclists: Questioning the Validity of the 3-Minute All-Out Test.

PURPOSE: New applications of the critical-power concept, such as the modeling of intermittent-work capabilities, are exciting prospects for elite cycling. However, accurate calculation of the required parameters is traditionally time invasive and somewhat impractical. An alternative single-test protocol (3-min all-out) has recently been proposed, but validation in an elite population is lacking. The traditional approach for parameter establishment, but with fewer tests, could also prove an acceptable compromise. METHODS: Six senior Australian endurance track-cycling representatives completed 6 efforts to exhaustion on 2 separate days over a 3-wk period. These included 1-, 4-, 6-, 8-, and 10-min self-paced efforts, plus the 3-min all-out protocol. Traditional work-vs-time calculations of CP and anaerobic energy contribution (W') using the 5 self-paced efforts were compared with calculations from the 3-min all-out protocol. The impact of using just 2 or 3 self-paced efforts for traditional CP and W' estimation was also explored using thresholds of agreement (8 W, 2.0 kJ, respectively). RESULTS: CP estimated from the 3-min all-out approach was significantly higher than from the traditional approach (402 ± 33, 351 ± 27 W, P < .001), while W' was lower (15.5 ± 3.0, 24.3 ± 4.0 kJ, P = .02). Five different combinations of 2 or 3 self-paced efforts led to CP estimates within the threshold of agreement, with only 1 combination deemed accurate for W'. CONCLUSIONS: In elite cyclists the 3-min all-out approach is not suitable to estimate CP when compared with the traditional method. However, reducing the number of tests used in the traditional method lessens testing burden while maintaining appropriate parameter accuracy.

Adherence, Compliance, and Health Risk Factor Changes following Short-Term Physical Activity Interventions.

BACKGROUND: Low physical activity (PA) levels are associated with poor health risk factor profiles. Intervention strategies to increase PA and quantify the rate and magnitude of change in risk factors are important. METHODS: Interventions were conducted over 40 days to increase PA in 736 insufficiently active (<150 min/wk PA) participants using either a pedometer or instructor-led group protocol. There were a further 135 active participants as controls. Major cardiovascular and metabolic risk factors, including fitness parameters, were measured before and after intervention. RESULTS: Adherence to the interventions was higher for the group versus pedometer participants (87.1% versus 79.8%) and compliance rates for achieving sufficient levels of PA (≥150 min/wk) were also higher for the group participants (95.8% versus 77.6%). Total weekly PA patterns increased by 300 and 435 minutes, for the pedometer and group participants, respectively. Improvements were found for waist girth, total cholesterol, aerobic fitness, and flexibility relative to controls. The change in vigorous PA, but not moderate PA, was a significant predictor of the change in eight of 11 risk factor variables measured. CONCLUSIONS: Rapid and dramatic increases in PA among previously insufficiently active adults can result in important health benefits.

A comparison of two short-term intensive physical activity interventions: methodological considerations.

BACKGROUND: Increases in chronic illness due to sedentary lifestyles and poor metabolic fitness have led to numerous intervention strategies to promote physical activity (PA). This paper describes the methodological strategies of two short-term PA interventions. Outcome measures reported are PA adherence and compliance rates during the intervention and at 3, 6 and 12-month follow-up. METHODS: The 40-day interventions were: a pedometer-based walking program (n = 251) and a group-based intensive program (n = 148). There was also an active control group (n = 135). Intervention subjects were prescribed PA each day and required to record all activity sessions (pedometer steps or energy expenditure from heart rate monitors). RESULTS: Compliance (≥ 150 min/wk PA) was highest post-intervention (81.1% and 64.5% for the group and pedometer subjects, respectively) and then progressively decreased across the 12-month follow-up period (final compliance rates were 53.5% and 46.6%, respectively) although they remained significantly higher than pre-intervention rates (zero %). There was significantly higher adherence to 6 months (75.0% and 64.9%), and compliance to 3 months (64.9% and 51.0%), for group versus pedometer subjects. The active control group maintained the highest adherence and compliance rates across the study. CONCLUSIONS: The group-based program resulted in higher adherence and compliance rates post-intervention although both types of interventions showed long-term effectiveness to increase activity patterns.

Automated external defibrillators in the Australian fitness industry.

Sudden cardiac arrest (SCA) occurs in many thousands of Australians each year. Scientific evidence shows an increased survival rate for individuals who receive electrical defibrillation in the first few minutes after SCA. In the last decade automated (rhythm-detecting) external defibrillators (AEDs) have become available that are portable and affordable. Although still relatively rare, there is still the potential that SCA may occur when a person undertakes physical activity. Consequently, health/fitness centres are increasingly recognised as higher risk sites that may benefit from placement of AEDs. There are no laws in Australia requiring health/fitness centres to install AEDs. However, several international and professional organisations have "strongly encouraged" larger centres to install AEDs. Guidelines and algorithms are presented to help estimate the risk of SCA in fitness centres. Fitness centre placement is particularly important if the clientele is older or has a 'high-risk' profile, for example, clients with cardiovascular, respiratory or metabolic disease. International negligence case law and duty of care principles suggests the standard of care required in health/fitness centres may be increasing. Therefore, it may be prudent to install AEDs in larger centres and those in which higher risk groups are physically active.