Training Load and Its Role in Injury Prevention, Part I: Back to the Future.

The purpose of this 2-part commentary series is† to explain why we believe our ability to control injury risk by manipulating training load (TL) in its current state is an illusion and why the foundations of this illusion are weak and unreliable. In part 1, we introduce the training process framework and contextualize the role of TL monitoring in the injury-prevention paradigm. In part 2, we describe the conceptual and methodologic pitfalls of previous authors who associated TL and injury in ways that limited their suitability for the derivation of practical recommendations. The first important step in the training process is developing the training program: the practitioner develops a strategy based on available evidence, professional knowledge, and experience. For decades, exercise strategies have been based on the fundamental training principles of overload and progression. Training-load monitoring allows the practitioner to determine whether athletes have completed training as planned and how they have coped with the physical stress. Training load and its associated metrics cannot provide a quantitative indication of whether particular load progressions will increase or decrease the injury risk, given the nature of previous studies (descriptive and at best predictive) and their methodologic weaknesses. The overreliance on TL has moved the attention away from the multifactorial nature of injury and the roles of other important contextual factors. We argue that no evidence supports the quantitative use of TL data to manipulate future training with the purpose of preventing injury. Therefore, determining "how much is too much" and how to properly manipulate and progress TL are currently subjective decisions based on generic training principles and our experience of adjusting training according to an individual athlete's response. Our message to practitioners is to stop seeking overly simplistic solutions to complex problems and instead embrace the risks and uncertainty inherent in the training process and injury prevention.

Quantification of energy expenditure of recreational football.

There is a strong relationship between low physical activity level and cardiovascular diseases (CVD). The popularity of football may be used to promote physical activity and previous evidence has shown it is effective to decrease the risk of CVD. However, the energy expenditure (EE) of recreational football is not well known but it is crucial to develop preventive health programmes. Fifteen sedentary middle-aged male participants were involved (mean ± SDs; age 43.9 ± 3.1 years, weight 83.0 ± 13.6 kg, height 174.9 ± 6.8 cm). EE was estimated from the heart rate (HR)-VO2 relation during 1-h 5-a-side matches (futsal). Participants covered 3412 ± 381 m in 52 ± 2 min, at an average HR of 85 ± 2% of maximum HR. Estimated EE during a recreational futsal match was 634 ± 92 kcal. One futsal recreational match corresponds to about 50% of American College of Sport Medicine recommended physical activity quantity per week. Based on this estimation: once, twice and 3 sessions per week are equivalent to 50% (634 kcal), 100% (1268 kcal) and 150% (1902 kcal), respectively, of EE suggested in international guidelines. This EE estimation may have important implications for designing recreational football training protocols in health programmes and dose response studies.

Women demonstrate more pain and worse function before THA but comparable results 12 months after surgery.

BACKGROUND: Many studies report differences in patient-reported outcome measures (PROMs) for men and women undergoing total hip arthroplasty (THA). Few studies have evaluated whether these are explained by corresponding differences in important preoperative factors. QUESTIONS/PURPOSES: (1) Are there differences between men and women in PROM scores preoperatively and 12 months after THA? (2) Do baseline differences in comorbidity, age, body mass index (BMI), and mental health status explain these differences in PROM scores? METHODS: Preoperatively, 300 patients completed the Oxford Hip Score (OHS), WOMAC, and SF-12; 261 (86%) of them (129 women, 64 ± 11 years; 132 men, 66 ± 10 years) completed the same questionnaires 12 months postoperatively and also rated the acceptability of their current symptoms and change in general health. RESULTS: Preoperatively, women showed worse scores than men in the OHS (-1.9; 95% confidence interval, -3.6 to -0.3) and WOMAC (-6.3; -10.9 to -1.7). At 12 months postoperatively, the absolute scores for all PROMs were not significantly different. After controlling for BMI, age, comorbidity, SF-12 mental health scores, and sociodemographic characteristics, the baseline differences remained. CONCLUSIONS: Surgeons may be more reluctant to operate on women than men because they perceive that, because of their worse baseline status, women are likely to have worse outcomes; however, given that we found no evidence for differences in patient-reported outcomes at 12 months, these suspicions would appear to be unfounded. Women and men can be expected to benefit to a similar extent from THA. LEVEL OF EVIDENCE: Level III, therapeutic study.

The assessment of maximal aerobic power with the multistage fitness test in young women soccer players.

The aims of this study were to assess the criterion validity and the accuracy in estimating maximal aerobic power (VO2max) of a popular shuttle running field test (multistage fitness test [MSFT]) in women soccer players. Twenty-six women soccer players (age 12.1+/-0.9 years, body mass 50+/-9.2 kg, and height 155+/-5.7 cm) were tested over separate occasions for VO2max (VO2max test) and MSFT performances with (MSFT peak oxygen uptake) or without (MSFT) gas analysis. Data showed that the VO2max estimation using the MSFT predicting nomogram was significantly lower than MSFT VO2peak (32.7+/-3.9 vs. 40.1+/-5.9 ml.kg(-1).min(-1); p<0.001). No significant difference between VO2max test and MSFT for maximal VO2 and heart rate (HR) was observed (38.7+/-4.7 vs. 40.1+/-5.9 ml.kg(-1).min(-1) and 203+/-5.3 vs. 200+/-9.8 beats.min(-1); p>0.05; n=15). The MSFT performance (950+/-213 m) results significantly correlated with MSFT-VO2peak (r=0.70; p<0.001). This study results showed that the MSFT predicting nomogram significantly underestimated VO2peak. Average difference being in the order of 23% of the estimated value. Resulting MSFT-VO2peak significantly related to MSFT performance, and this test may be considered as an indirect measure of individual VO2max in young women soccer players. Furthermore, MSFT may be used as a valid test to assess VO2peak and HRmax when a portable gas analyzer and a HR monitor are available. However, great individual differences may occur. In light of this study results, it is suggested to consider MSFT performance (distance covered) and not estimated VO2max when dealing with young women soccer players.

Assessment of hip abductor muscle strength. A validity and reliability study.

BACKGROUND: Hip abductors are the most important muscles around the hip joint. It is therefore essential to assess their function in a valid and reliable way. Since the optimal body posture for the assessment of hip abductor strength is unknown, we tested the validity and reliability of unilateral hip abductor strength assessment in three different body positions. We hypothesized that the validity would be better in the side-lying position because of the consistent stabilization of the contralateral (untested) hip. METHODS: Sixteen healthy subjects participated in two identical testing sessions. Unilateral isometric hip abductor muscle strength was measured, with use of a stabilized commercial dynamometer, with the subject in the side-lying, supine, and standing positions. Construct validity was based on concomitant recordings of gluteus medius electromyographic activity from the tested and contralateral hips. The body position permitting greater muscle activation and abductor strength on the tested hip, while minimizing muscle activation in the contralateral hip (that is, lower contralateral-to-tested electromyographic ratio), was considered the most valid. Coefficients of variation, the Bland and Altman limits of agreement, and intraclass correlation coefficients were calculated to determine test-retest reliability of hip abductor strength. RESULTS: Maximal hip abductor strength was significantly higher in the side-lying position compared with the standing and supine positions (p < 0.05). The contralateral-to-tested electromyographic ratio for the side-lying position was significantly lower than that for the supine and the standing position (p < 0.01). Test-retest reliability of strength measurements in terms of coefficients of variation (3.7% for side-lying, 6.1% for supine, and 4.2% for standing) and limits of agreement (+/-6.9% for side-lying, +/-8.4% for supine, and +/-7.5% for standing) was better in the side-lying position. All intraclass correlation coefficients were high to moderate (0.90 for side-lying, 0.83 for supine, and 0.88 for standing). CONCLUSIONS: The side-lying body position offers the most valid and reliable assessment of unilateral hip abductor strength.

Money matters: exploiting the data from outcomes research for quality improvement initiatives.

In recent years, there has been an increase in studies that have sought to identify predictors of treatment outcome and to examine the efficacy of surgical and non-surgical treatments. In addition to the scientific advancement associated with these studies per se, the hospitals and clinics where the studies are conducted may gain indirect financial benefit from participating in such projects as a result of the prestige derived from corporate social responsibility, a reputational lever used to reward such institutions. It is known that there is a positive association between corporate social performance and corporate financial performance. However, in addition to this, the research findings and the research staff can constitute resources from which the provider can reap a more direct benefit, by means of their contribution to quality control and improvement. Poor quality is costly. Patient satisfaction increases the chances that the patient will be a promoter of the provider to friends and colleagues. As such, involvement of the research staff in the improvement of the quality of care can ultimately result in economic revenue for the provider. The most advanced methodologies for continuous quality improvement (e.g., six-sigma) are data-driven and use statistical tools similar to those utilized in the traditional research setting. Given that these methods rely on the application of the scientific process to quality improvement, researchers have the adequate skills and mind-set to embrace them and thereby contribute effectively to the quality team. The aim of this article is to demonstrate by means of real-life examples how to utilize the findings of outcome studies for quality management in a manner similar to that used in the business community. It also aims to stimulate research groups to better understand that, by adopting a different perspective, their studies can be an additional resource for the healthcare provider. The change in perspective should stimulate researchers to go beyond the traditional studies examining predictors of treatment outcome and to see things instead in terms of the "bigger picture", i.e., the improvement of the process outcome, the quality of the service.

Physiological assessment of aerobic training in soccer.

Physiological assessment of soccer training usually refers to the measurement of anatomical, physiological, biochemical and functional changes specific to the sport discipline (training outcome). The quality, quantity and organization of physical exercises (training process) are, on the other hand, usually described by the external work imposed by the coach on his or her athletes. In this review, we demonstrate that this approach is not appropriate in soccer, as training is often based on group exercises. The physiological stress (internal load) induced by such training often differs between individuals. Here, we present some physiological laboratory-based tests and field tests used to evaluate training outcomes in soccer, together with methods based on heart rate and perceived exertion to quantify internal load imposed during training. The integrated physiological assessment of both training outcome and process allows researchers: (1) to improve interpretation of physical tests used to verify the effectiveness of training programmes; (2) to evaluate the organization of the training load in order to design periodization strategies; (3) to identify athletes who are poor responders; (4) to control the compliance of the training completed to that planned by the coach; and (5) to modify the training process before the assessment of its outcome, thus optimizing soccer performance.