1,721,021 research outputs found
Internal and external training load: 15 years on
No full textExercise is a stressor that induces various psychophysiological responses, which mediate cellular adaptations in many organ systems. To maximize this adaptive response, coaches and scientists need to control the stress applied to the athlete at the individual level. To achieve this, precise control and manipulation of the training load are required. In 2003, the authors introduced a theoretical framework to define and conceptualize the measurable constructs of the training process. They described training load as having 2 measurable components: internal and external load. The aim of this commentary is to extend, clarify, and refine both the theoretical framework and the definitions of internal and external training load to avoid misinterpretation of this concept
Return to competition after an Achilles tendon rupture using both on and off the field load monitoring as guidance: A case report of a top-level soccer player
Full text linkOBJECTIVES: To describe the Return to competition after Achilles Tendon rupture (ATR) in an elite soccer player. DESIGN: Case report. SETTING: Return to sport (RTS) of a professional soccer player who suffered an ATR during a match. The RTS phase started 15 weeks after surgery and specific on-field activities were gradually introduced. Criteria used to monitor the transition through the different phases were strength and endurance of the calf muscle and ability to sustain specific on-field training loads (TL) monitored with Global Positioning System and heart-rate system. TLs were weekly compared to pre-injury values to evaluate recovery and to prescribe future sessions. PARTICIPANT: A 39-year-old (height 178 cm, weight 75 kg) elite soccer defender player, playing in Italian Serie-A league. RESULTS: Days of absence were lower compared to a cohort presented in UEFA study (119 versus 161 ± 65 days, respectively). External-TL and Internal-TL were organized to gradually increase during RTS and resulted in higher values prior to return to competition compared to pre-injury values. Concentric plantar flexion peak torque increased till 9th months after surgery. CONCLUSIONS: Monitoring of the field activities allowed comparison with pre-injury values and provided a useful and functional criteria to pass return to team activity and competition
What Role Do Chronic Workloads Play in the Acute to Chronic Workload Ratio? Time to Dismiss ACWR and Its Underlying Theory
Full text linkAim The aim of this study was to examine the associations between the injury risk and the acute (AL) to chronic (CL) workload ratio (ACWR) by substituting the original CL with contrived values to assess the role of CL (i.e., the presence and implications of statistical artefacts). Methods Using previously published data, we generated a contrived ACWR by dividing the AL by fixed and randomly generated CLs, and we compared these results to real data. We also reproduced previously reported subgroup analyses, including dichotomising players' data above and below the median CL. Our analyses follow the same, previously published modelling approach. Results The analyses with original data showed effects compatible with higher injury risk for ACWR only (odd ratios, OR: 2.45, 95% CI 1.28-4.71). However, we observed similar effects by dividing AL by the "contrived" fixed and randomly generated CLs: OR 1.95 (1.18-3.52) dividing by 1510 (average CL); and OR ranging from 1.16 to 2.07, using random CL 1.53 (mean). Random ACWRs reduced the variance relative to the original AL and further inflated the ORs (mean OR 1.89, from 1.42 to 2.70). ACWR causes artificial reclassification of players compared to AL alone. Finally, neither ACWR nor AL alone confer a meaningful predictive advantage to an intercept-only model, even within the training sample (c-statistic 0.574/0.544 vs. 0.5 in both ACWR/AL and intercept-only models, respectively). Discussion ACWR is a rescaling of the explanatory variable (AL, numerator), in turn magnifying its effect estimates and decreasing its variance despite conferring no predictive advantage. Other ratio-related transformations (e.g., reducing the variance of the explanatory variable and unjustified reclassifications) further inflate the OR of AL alone with injury risk. These results also disprove the etiological theory behind this ratio and its components. We suggest ACWR be dismissed as a framework and model, and in line with this, injury frameworks, recommendations, and consensus be updated to reflect the lack of predictive value of and statistical artefacts inherent in ACWR models
Effects of low vs moderate dose of recreational football on cardiovascular risk factors
No full textThis study aimed to compare the effectiveness of recreational football performed once (LOW) vs. twice (MOD) a week on cardiovascular risk factors in healthy, sedentary men. Body composition, resting blood pressure, blood lipid profile and maximal oxygen consumption (VO2max) were measured at baseline, after a 12-week control and training period, using an interrupted time series study (study 1, n=18: n=8, LOW and n=10, MOD) nested in a randomised parallel trial (study 2, n=34: n=18 LOW and n=16 MOD). After the intervention in the study 1, LDL-Cholesterol (-12.3 mg•dL-1 [-22.7 to -2.0]) and VO2max (4.5 ml•kg-1•min-1 [1.2 to 7.8 ]) changed in LOW whereas differences were found in weight (-2.1 kg [-3.7 to -0.4]), BMI (-0.7 kg•m-2 [-1.2 to -0.1]), total cholesterol (-22.2 mg•dL-1 [-36.0 to -8.4]), no-HDL-cholesterol (-17.5 mg•dL-1 [-30.5 to -4.5]), LDL-cholesterol (-14.9 mg•dL-1 [-23.6 to -6.2]) and VO2max (5.7 ml•kg-1•min-1 [2.8 to 8.6]) in MOD. Study 2 showed no evidence of differences between groups. Our results therefore, suggest positive health effects of recreational football even when performed at low frequency as it can happen in real context
Quantification of energy expenditure of recreational football
No full textThere 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 +/- 3.1years, weight 83.0 +/- 13.6kg, height 174.9 +/- 6.8cm). EE was estimated from the heart rate (HR)-VO2 relation during 1-h 5-a-side matches (futsal). Participants covered 3412 +/- 381m in 52 +/- 2min, 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
Effects of One Versus Two Games a Week on Physical and Subjective Scores of Sub-Elite Soccer Players
No full textThe physical-performance profiles of subelite male footballers were monitored during 6 wk of a competitive season. The same squad of players played either 1 (1G, n = 15) or 2 (2G, n = 15) competitive matches per week. On weeks 0, 3, and 6, 48 h postmatch, players completed countermovement jump (CMJ), 10- and 20-m sprints, the Yo-Yo Intermittent Recovery Test (YYIRT), and the Recovery-Stress Questionnaire. Both groups undertook 2 weekly training sessions. The 2G showed after 6 wk lower YYIRT (-11% to 3%, 90% CI -15.8% to -6.8%; P < .001) and CMJ performances (-18.7%, -21.6 to -15.9%; P = .007) and higher 10-m (4.4%, 1.8-6.9%; P = .007) and 20-m sprints values (4.7%, 2.9% to 6.4%; P < .001). No differences were found at 3 wk (.06 < P < .99). No changes over time (.169 < P < .611) and no differences time × group interactions (.370 < P < .550) were found for stress, recovery, and the Stress Recovery Index. In conclusion players' ability to sprint, jump, and perform repeated intense exercise was impaired when playing 2 competitive matches a week over 6 wk
Use of CR100 Scale for Session-RPE in Soccer and Interchangeability With CR10
Full text linkPurpose: To examine the construct validity of the session rating perceived exertion (s-RPE) assessed with the Borg CR100® scale to measure training loads in elite soccer and to examine if the CR100® is interchangeable and can provide more accurate ratings compared to the CR10® scale. Methods: Two studies were conducted. The validity of the CR100® was determined in 19-elite soccer players (age 28 ± 6 y, height 180 ± 7 cm, body mass 77 ± 6 kg) during training sessions through correlations with Edwards heart rate method (study one). The interchangeability with CR10® was assessed in 78 soccer players (age 19.3 ± 4.1 y, height 178 ± 5.9 cm, body mass 71.4 ± 6.1 kg) through Bland-Altman method and correlations between change scores in different sessions. To examine whether the CR100® is more fine graded than the CR10®, the proportion of responses corresponding to the verbal expressions were calculated (study two). Results: Individual correlations between Edwards’ and s-RPE were large to very large (0.52 to 0.85). The mean difference between the two scales was -0.3 ± 0.33 AU (90% CI -0.41 to -0.29 AU) with 95% limits of agreements 0.31 to -0.96 AU. Correlations between scales and between changes scores were nearly perfect (0.95 and 0.91 to 0.98). Ratings corresponding to the verbal anchors were 49% in CR10® and 26% in CR100®. Conclusions: The CR100® is valid for assessing the training load in elite soccer players. It can be used interchangeably with the CR10® and may provide more precise measures of exercise intensity
Effect of training-session intensity distribution on session rating of perceived exertion in soccer players
Full text linkPURPOSE:
To examine the effect of different exercise-intensity distributions within a training session on the session rating of perceived exertion (RPE) and to examine the timing of measure on the rating.
METHODS:
Nineteen junior players (age 16±1 y, height 173±5 cm, body mass 64±6 kg) from a Swiss soccer team were involved in the study. Percentage of heart rate maximum (%HR) and RPE (Borg CR100®) were collected in 4 standardized training sessions (conditions). The Total Quality of Recovery scale (TQR) and a visual analogue scale (VAS) for pain of the lower limbs were used to control for the effect of pretraining fatigue. Every session consisted of three 20-min blocks of different intensities (ie, low-moderate-high) performed in a random order. RPE was collected after every block (RPE5), immediately after the session (RPE-end), and 30 min after the session (RPE30).
RESULTS:
RPE5s of each block were different depending on the distribution sequence (P<.0001). RPE-end, TQR, and VAS values were not different between conditions (P=.57, P=.55, and P=.96, respectively). The %HR was significantly different between conditions (P=.008), with condition 3 higher than condition 2 (74.1 vs 70.2%, P=.02). Edwards training loads were not significantly different between conditions (P=.09). RPE30 was not different from RPE-end (P>.05).
CONCLUSIONS:
The current results show that coaches can design training sessions without concern about the influence of the within-session distribution of exercise intensity on session-RPE and that RPE can be collected at the end of the session or 30 min later
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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