Assessment of Maximum Oxygen Uptake in Elite Youth Soccer Players: A Comparative Analysis of Smartwatch Technology, Yoyo Intermittent Recovery Test 2, and Respiratory Gas Analysis.

The maximum oxygen uptake (VO2max) is a critical factor for endurance performance in soccer. Novel wearable technology may allow frequent assessment of V̇O2max during non-fatiguing warm-up runs of soccer players with minimal interference to soccer practice. The aim of this study was to assess the validity of VO2max provided by a consumer grade smartwatch (Garmin Forerunner 245, Garmin, Olathe, USA, Software:13.00) and the YoYo Intermittent Recovery Run 2 (YYIR2) by comparing it with respiratory gas analysis. 24 trained male youth soccer players performed different tests to assess VO2max: i) a treadmill test employing respiratory gas analysis, ii) YYIR2 and iii) during a non-fatiguing warm-up run of 10 min wearing a smartwatch as recommended by the device-manufacturer on 3 different days within 2 weeks. As the device-manufacturer indicates that validity of smartwatch-derived VO2max may differ with an increase in runs, 16 players performed a second run with the smartwatch to test this claim. The main evidence revealed that the smartwatch showed an ICC of 0.37 [95% CI: -0.25; 0.71] a mean absolute percentage error (MAPE) of 5.58% after one run, as well as an ICC of 0.54 [95% CI: -0.3; 8.4] and a MAPE of 1.06% after the second run with the smartwatch. The YYIR2 showed an ICC of 0.17 [95% CI: -5.7; 0.6]; and MAPE of 4.2%. When using the smartwatch for VO2max assessment in a non-fatiguing run as a warm-up, as suggested by the device manufacturer before soccer practice, the MAPE diminishes after two runs. Therefore, for more accurate VO2max assessment with the smartwatch, we recommend to perform at least two runs to reduce the MAPE and enhance the validity of the findings.

Effect of High-Intensity With Short-Duration Re-Warm-Up on Subsequent Performance in a Cold Environment.

ABSTRACT: Yamashita, Y and Umemura, Y. Effect of high-intensity with short-duration re-warm up on subsequent performance in a cold environment. J Strength Cond Res 38(6): e280-e287, 2024-The aim of this study was to investigate the effect of high-intensity, short-duration re-warm-up (RW) during half time (HT) on subsequent performance in a cold environment. Eleven male subjects (age, 21 ± 2 years; height, 172.4 ± 4.5 cm; body mass, 65.6 ± 7.1 kg; V̇ o2 max, 47.5 ± 4.8 ml·kg -1 ·min -1 ) performed 2 experimental trials comprising 40 minutes of intermittent cycling exercise, which consisted of 15-second rest, 25-second unloading cycling, 10-second high-intensity cycling, and 70-second moderate-intensity cycling as the first half. In the second half, a cycling intermittent-sprint protocol (CISP) was performed, separated by a 15-minute HT period in cold conditions (5 °C, 50% relative humidity). Two experimental trials were included in a random order: (a) approximately 1 minute of high-intensity, short-duration RW (3 sets of 3-second maximal pedaling [body weight × 0.075 kp]) trial high-intensity intermittent cycling trials (HII); (b) 15 minutes of seated rest trial (CON). Cycling intermittent-sprint protocol consisted of 10 sets of a 2-minute exercise protocol, and each set consisted of 10-second rest, 5-second maximal pedaling (body weight × 0.075 kp), and 105-second active recovery at 50% maximum oxygen uptake (V̇ o2 max). Peak power output of 5-second maximal pedaling during CISP was higher in HII trials than in CON trials (HII: 807 ± 81 W, CON: 791 ± 78 W, p < 0.05). There was no significant difference in rectal temperature between trial types ( p > 0.05). These results suggest that high-intensity, short-duration RW may be a useful HT strategy for improving subsequent performance in cold environments.

Effect of Level of Competition and Drill Typology on Internal and External Load in Male Volleyball Players During the Preseason Period.

PURPOSE: This study aimed at evaluating the effect of level of competition and drill typology on loads during the preseason period in male volleyball players. METHODS: Internal (percentage of peak heart rate [HR] and summated HR zone) and external (PlayerLoad per minute, total and high accelerations per minute [tACCmin and hACCmin], decelerations per minute [tDECmin and hDECmin], and jumps per minute [tJUMPmin and hJUMPmin]) loads were monitored across a 5-week preseason period in 12 Division 1 (age: 22.5 [3.9] y; stature: 188 [6.2] cm; body mass: 85 [11.6] kg; training experience: 9.4 [4.2] y) and 12 Division 2 (age: 20.7 [2.9] y; stature: 186 [6.2] cm; body mass: 77.8 [9.6] kg; training experience: 5.6 [2.3] y) male volleyball players. Furthermore, differences in load were assessed for each drill typology (warm-up, conditioning, technical, tactical, and integral). RESULTS: No effects (P > .05) of level of competition on the internal (except for summated HR zone, P = .05) and external loads (except for tJUMPmin, P = .002) were found. Differently, drill typologies showed an effect (P < .001) on all the investigated internal- and external-load measures. The main post hoc results revealed higher (P < .05) percentage of peak HR, summated HR zone, PlayerLoad per minute, and tACCmin in warm-up and conditioning drills, while higher (P < .05) hDECmin and hJUMPmin were found in tactical and integral drills. CONCLUSIONS: These results suggest that volleyball coaches use warm-up and conditioning drills when aiming at increasing the internal loads, PlayerLoad per minute, and tACCmin, while tactical and integral drills should be preferred to enhance the number of hDECmin and hJUMPmin.

A warm-up strategy with or without voluntary contraction on athletic performance, lower-leg temperature, and blood lactate concentration.

It is unclear whether temperature-related warm-up effects can be accomplished by passive warm-up (e.g., by external heat). Therefore, this study compared the effects of two different warm-up protocols with and without voluntary contraction on subsequent sprinting and jumping performance. Eighteen healthy male collegiate students (23.3 ± 2.4 years, 173.8 ± 7.2 cm, 70.5 ± 9.3 kg) randomly experienced 10 min of active (jogging on a treadmill; belt speed: 9.0 km/h at a 1% incline) and passive warm-up (lying down in the warm-up chamber; inner ambient temperature set at 35°C) protocols, followed by ten sets of intermittent exercises in two separate sessions. Athletic performance, lower-leg muscle temperature, and blood lactate concentration were statistically compared using analysis of variance with Tukey-Kramer post-hoc comparisons. Cohen's d effect sizes (ES) were also calculated. There was no warm-up protocol effect over time on 20 m sprint times (condition × time: F9,323 = 1.26, p = 0.25). Maximal vertical jump heights were different (condition × time: F9,323 = 2.0, p = 0.04) such that subjects who performed the active warm-up protocol jumped higher (51.4 cm) than those who did the passive warm-up (49.2 cm, p = 0.04). There was a warm-up protocol effect over time on lower-leg muscle temperature (condition × time: F12,425 = 13.99, p<0.0001) in that there was a 5.5% and 5.8% increase after active (32.8 to 34.6°C, ES = 2.91) and passive (32.9 to 34.9°C, ES = 3.28) warm-up protocols, respectively. Blood lactate concentration was different (condition × time: F2,85 = 3.61, p = 0.03) since the values at the post-warm-up measurements were different between warm-up conditions (active: 4.1 mmol/L; passive: 1.5 mmol/L, p = 0.004, ES = 1.69). Subsequent sprint and jump performance did not differ between the duration- and muscle temperature-matched active and passive warm-up protocols. Non-thermal effects from the warm-up activity may be minimal for sprinting and jumping performance in recreationally active males.

Revisiting the 'Whys' and 'Hows' of the Warm-Up: Are We Asking the Right Questions?

The warm-up is considered beneficial for increasing body temperature, stimulating the neuromuscular system and overall preparing the athletes for the demands of training sessions and competitions. Even when warm-up-derived benefits are slight and transient, they may still benefit preparedness for subsequent efforts. However, sports training and competition performance are highly affected by contextual factors (e.g., how is the opponent acting?), and it is not always clear what should be the preferred warm-up modalities, structure and load for each athlete and context. Further, we propose that the warm-up can also be used as a pedagogical and training moment. The warm-up may serve several different (albeit complementary) goals (e.g., rising body temperature, neuromuscular activation, attentional focus) and be performed under a plethora of different structures, modalities, and loads. The current commentary highlights the warm-up period as an opportunity to teach or improve certain skills or physical capacities, and not only as a preparation for the subsequent efforts. Moreover, the (justified) call for individualized warm-ups would benefit from educating athletes about exploring different warm-up tasks and loads, providing a broad foundation for future individualization of the warm-up and for more active, engaged, and well-informed participation of the athletes in deciding their own warm-up practices.

Physiological mechanisms associated with the use of a passive heat intervention: positive implications for soccer substitutes.

PURPOSE: Soccer substitutes are exposed to periods of limited activity before entering match-play, likely negating benefits of active warm-ups. This study aimed to determine the effects of using a passive heat intervention following a pre-match, and half-time warm-up, on muscle and core temperature in soccer players during ambient (18 °C) and cold (2 °C) conditions. METHODS: On four occasions, 8 male players, completed a pre-match warm-up, followed by 45 min of rest. Following this, participants completed a half-time re-warm-up followed by an additional 45 min of rest, simulating a full match for an unplaying substitute. During periods of rest, participants wore either standardised tracksuit bottoms (CON), or heated trousers (HEAT), over typical soccer attire. RESULTS: Vastus lateralis temperature declined less in HEAT compared to CON following the 1st half in 2 °C (Δ - 4.39 ± 0.81 vs. - 6.21 ± 1.32 °C, P = 0.002) and 18 °C (Δ - 2.48 ± 0.71 vs. - 3.54 ± 0.88 °C, P = 0.003). These findings were also observed in the 2nd half for the 2 °C (Δ - 4.36 ± 1.03 vs. - 6.26 ± 1.04 °C, P = 0.002) and 18 °C (Δ - 2.85 ± 0.57 vs. - 4.06 ± 1 °C, P = 0.018) conditions. In addition, core temperature declined less in HEAT compared to CON following the 1st (Δ - 0.41 ± 0.25 vs. - 0.84 ± 0.41 °C, P = 0.037) and 2nd (Δ - 0.25 ± 0.33 vs. - 0.64 ± 0.34 °C, P = 0.028) halves of passive rest in 2 °C, with no differences in the 18 °C condition. Perceptual data confirmed that participants were more comfortable in HEAT vs. CON in 2 °C (P < 0.01). CONCLUSIONS: Following active warm-ups, heated trousers attenuate the decline in muscle temperature in ambient and cold environments.

Using Deadlifts as a Postactivation Performance Enhancement Strategy in Warm-ups in Football.

ABSTRACT: Abade, E, Brito, J, Gonçalves, B, Saura, L, Coutinho, D, and Sampaio, J. Using deadlifts as a postactivation performance enhancement strategy in warm-ups in football. J Strength Cond Res 37(9): 1821-1827, 2023-Postactivation performance enhancement activities may be relevant warm-up strategies aiming to improve subsequent physical performance. The purpose of the current study was to investigate the effects of adding barbell deadlift or hex-bar deadlift exercises to current warm-up routines on running and jumping performances in football players. Ten highly trained male football players participated in the study during the competitive phase of the season. All players performed 3 protocols in the same week: a standard warm-up that included players' regular routines and 2 other protocols with the addition of barbell or hex-bar deadlift, after the end of the warm-up (3 sets of 3 reps, progressing set by set from 60% to 85% repetition maximum). All protocols had the same time interval between pretest (immediately after the warm-up) and posttest (15 minutes after the warm-up). Vertical jumping (countermovement jump [CMJ]; Abalakov jump [AJ]) and running performances (505 test) were impaired 15 minutes after the standard warm-up (CMJ: -6.7 ± 4.2%; AJ: -8.1 ± 8.4%; and 505 time: 1.4 ± 2.5%). For warm-up with the addition of barbell deadlift, vertical jump increased by 4.3 ± 5.6% (Cohen's dunb : 0.23 [0.02-0.47]) and 505 time decreased by -5.9 ± 3.6% (Cohen's dunb : 0.97 [-1.68 to -0.43]). The warm-up with hex-bar deadlift led to trivial changes for CMJ and AJ, but 505 time decrease by -2.7 ± 2.6% (Cohen's dunb : -0.53 [-1.01 to -0.13]). The deadlift exercise can be added to warm-up routines to maintain or even enhance acute physical performance. However, coaches and practitioners should be aware that performance enhancements resultant from deadlift may vary according to individual physical profiles.

Acute Effects of Combining Dynamic Stretching and Vibration Foam Rolling Warm-up on Lower-Limb Muscle Performance and Functions in Female Handball Players.

ABSTRACT: Chen, CH, Chiu, CH, Tseng, WC, Wu, CY, Su, HH, Chang, CK, and Ye, X. Acute effects of combining dynamic stretching and vibration foam rolling warm-up on lower-limb muscle performance and functions in female handball players. J Strength Cond Res 37(6): 1277-1283, 2023-The purpose of this study was to compare the acute effects of 3 warm-up protocols on knee flexor and extensor muscles performance in elite female collegiate handball players. Ten female handball players with poor hamstring flexibility completed 3 randomly sequenced experimental visits. During each visit, a different warm-up protocol (general running warm-up [GW], dynamic stretching [DS], or DS combined with vibration foam rolling [DS + VR]) was delivered before the subsequent tests: quadriceps and hamstring muscle stiffness, knee extension and flexion range of motion (ROM), knee joint position sense, knee extension and flexion isokinetic strength with hamstring-quadriceps strength ratio, and muscle endurance during fatiguing exercise. Relative to the GW, the DS + VR protocol resulted in significantly greater knee flexion ROM (mean ± SD : DS + VR = 79.4° ± 7.7°; GW = 69.3° ± 9.6°) and lower hamstring muscle stiffness (DS + VR = 253.33 ± 36.20 N·m -1 ; GW = 292.89 ± 24.28 N·m -1 ). In addition, the DS + VR protocol also yielded greater hamstring muscle endurance than the other 2 protocols did (fatigue percentage: DS + VR = 30.24% ± 10.84%; GW = 41.40% ± 8.98%; DS = 42.22% ± 9.42%). Therefore, the results of this experiment suggest that it can be more beneficial for the female handball players to warm-up with the DS + VR, rather than the GW and DS protocols.

Electric Muscle Stimulation (EMS) Does Not Improve Anaerobic Performance Measures During a Repeated Wingate Test.

Introduction: The aim of this study was to examine differences between a control warm-up and an Electric Muscle Stimulation (EMS)-induced warm-up in off-road cyclists when examining anaerobic performance measures from a repeated Wingate test (WAnT). Methods: Twelve trained off-road cyclists completed a randomized crossover study (age: 31 ± 10 years, height: 176.79 ± 6.09 cm, body mass: 74.57 ± 4.77 kg). Participants completed two randomized, separate testing sessions involving a control warm-up and an EMS warm-up before undergoing the repeated WAnT, which was used to collect anaerobic performance and physiolo- gical measures during both sessions. High-frequency EMS was applied to the knee extensor muscles for 4 min after a standardized warm-up during the EMS session. Results: Analysis revealed that there were no significant differences between mean power output, peak power output, and percentage decrement between the two sessions. The EMS session resulted in significantly lower average HR values and significantly lower differences in pre-to-post-test blood lactate values when compared to the control session. Discussion: According to the results of this study, an acute application of EMS is not a useful tool for off-road cyclists to improve power output or maintain anaerobic capacity. Hence, its use before competition is questionable.

Impact of Warm-Up on Muscle Temperature and Athletic Performance.

Purpose: We performed two studies to investigate: the minute-by-minute changes in muscle temperature following a 20-min warm-up routine (Study-1) and the impact of the typical post-warm-up period of inactivity on the performance of basketball athletes (Study-2). Method: In Study-1, 26 males (age: 23.6 ± 6.2 yr; BMI: 24.1 ± 3.1 kg/m2) performed a 20-min cycling warm-up and then rested for 20 min. Tibialis anterior muscle temperature was assessed throughout. In Study-2, six male professional basketball players (age: 24.9 ± 4.6 yr; BMI: 25.5 ± 1.8 kg/m2) performed a series of basketball performance tests after a 20-min warm-up, as well as 9-min and 23-min into a post-warm-up period of inactivity. Results: On average, muscle temperature increased by 0.1°C every minute during warm-up and dropped by the same amount every minute during inactivity. The increase during warm-up and the decrease during inactivity were higher at the start of each period. A 9-min inactivity period is accompanied by 3.8 ± 0.6% reduction in countermovement jump (p = .046). A 23-min inactivity period is accompanied by 7.3 ± 0.7% reduction in lay-up points (p = .027). Conclusion: These two studies show that a 20-min warm-up routine increases muscle temperature but this benefit is lost after a typical post-warm-up inactivity period in high-level basketball, leading to reductions in certain aspects of athletic performance.

Warm-up increases muscle temperature and benefits performance, but it is not clear how long these benefits are active for.In sports, such as basketball, athletes may stay on the bench for a considerable amount of time post warm-up, and then are required to enter the game and perform at maximum intensity despite that they may have cooled down, posing an important knowledge gap for athletes, coaches, and event organizers.We found that muscle temperature increases, on average, by 0.1°C every minute during a 20-min warm-up routine and drops by the same amount every minute during a 20-min post-warm-up inactivity period.In total, the two studies presented in this article show that a warm-up routine increases muscle temperature, but this benefit is lost after a typical post-warm-up period of inactivity in high-level basketball, leading to reductions in certain aspects of athletic performance.

Swimming performance, physiology, and post-activation performance enhancement following dryland transition phase warmup: A systematic review.

BACKGROUND: In swimming, the period between the end of the swimming warmup and the beginning of competition is critical to performance, here termed the transition phase. Several options are available during this phase, necessitating a systematic review to understand if optimal strategies exist. OBJECTIVES: To synthesise and critically evaluate the current literature investigating land-based warmup interventions on subsequent performance in competitive swimmers. METHODS: A search of three electronic databases (PubMed, EBSCO SPORTDiscus and Web of Science) was conducted to identify original studies until February 2022. Selection criteria dictated that (i) a control condition was used, (ii) participants were ≥ 15 years of age, (iii) a pool-based warmup was done prior to the land-based warmup. A total of 25 articles met the selection criteria. RESULTS: Reducing the transition phase duration by at least half led to consistently faster time-trial times of between 1.1-1.5% for all included studies. Passive warmups using clothing interventions resulted in mostly faster time-trial's of 0.4-0.8% with increases in skin temperature frequent, though little change occurred in core temperature. The methodology of passive respiratory warmups were vastly different with positive time-trial's effects ranging between 0.9-1.1% for two studies, though one reported no meaningful difference. Active warmups led to consistently faster time-trial's between 0.7-0.9%, though the unpinning factors are not clear. Warmups which combined passive and active options frequently led to faster time-trial's between 0.8-3%. Upper and combined limb post-activation performance enhancement led to mostly unfavourable time-trial changes. Lower limb exclusive protocols results were inconsistent, with limited beneficial effects on time-trial or start performance reported following plyometric protocols. However, there does appear merit in heavier loaded lower limb protocols. CONCLUSION: Each of a reduced transition phase length, and passive, active or combination warmup have demonstrated improvements in swimming performance. Conversely, PAPE protocols should be used with caution, especially when including the upper limbs.

Effects of different inspiratory muscle warm-up loads on mechanical, physiological and muscle oxygenation responses during high-intensity running and recovery.

Inspiratory muscle warm-up (IMW) has been used as a resource to enhance exercises and sports performance. However, there is a lack of studies in the literature addressing the effects of different IMW loads (especially in combination with a shorter and applicable protocol) on high-intensity running and recovery phase. Thus, this study aimed to investigate the effects of three different IMW loads using a shorter protocol on mechanical, physiological and muscle oxygenation responses during and after high-intensity running exercise. Sixteen physically active men, randomly performed four trials 30 s all-out run, preceded by the shorter IMW protocol (2 × 15 breaths with a 1-min rest interval between sets, accomplished 2 min before the 30 s all-out run). Here, three IMW load conditions were used: 15%, 40%, and 60% of maximal inspiratory pressure (MIP), plus a control session (CON) without the IMW. The force, velocity and running power were measured (1000 Hz). Two near-infrared spectroscopy (NIRS) devices measured (10 Hz) the muscle's oxygenation responses in biceps brachii (BB) and vastus lateralis (VL). Additionally, heart rate (HR) and blood lactate ([Lac]) were also monitored. IMW loads applied with a shorter protocol promoted a significant increase in mean and minimum running power as well as in peak and minimum force compared to CON. In addition, specific IMW loads led to higher values of peak power, mean velocity (60% of MIP) and mean force (40 and 60% of MIP) in relation to CON. Physiological responses (HR and muscles oxygenation) were not modified by any IMW during exercise, as well as HR and [Lac] in the recovery phase. On the other hand, 40% of MIP presented a higher tissue saturation index (TSI) for BB during recovery phase. In conclusion, the use of different loads of IMW may improve the performance of a physically active individual in a 30 s all-out run, as verified by the increased peak, mean and minimum mechanical values, but not in performance assessed second by second. In addition, 40% of the MIP improves TSI of the BB during the recovery phase, which can indicate greater availability of O2 for lactate clearance.

Sensory enhancement of warm-up amplifies subsequent grip strength and cycling performance.

PURPOSE: In sport and exercise, warm-ups induce various physiological changes that facilitate subsequent performance. We have shown that delivering patterned stimulation to cutaneous afferents during sprint cycling mitigates fatigue-related decrements in performance, and that repeated sensory stimulation amplifies spinal reflex excitability. Therefore, the purpose of this study was to assess whether sensory enhancement of warm-up would affect subsequent high-intensity arm cycling performance. METHODS: Participants completed three experimental sessions, in which they randomly performed either a control, stim, or sleeve warm-up condition prior to maximal duration arm cycling. During the control condition, warmup consisted of low-intensity arm cycling for 15 min. The stim condition was the same, except they received alternating pulses (400 ms, 50 Hz) of stimulation just above their perceptual threshold to the wrists during warm-up. The third condition required participants to wear custom fabricated compression sleeves around the elbow during warm-up. Grip strength and spinal reflex excitability were measured before and after each warm-up and fatigue protocol, which required participants to arm cycle at 85% of peak power output until they reached volitional fatigue. Peak power output was determined during an incremental test at minimum 72 h prior to the first session. RESULTS: Both sensory enhanced warm-up conditions amplified subsequent high-intensity arm cycling performance by ~ 30%. Additionally, the stim and sleeve warm-up conditions yielded improvements in grip strength (increased by ~ 5%) immediately after the sensory enhanced warm-ups. Ergogenic benefits from the sensory enhanced warm-up conditions did not differ between one another. CONCLUSION: These findings demonstrate that enhanced sensory input during warm-up can elicit improvements in both maximal and submaximal performance measures.

The influence of recovery period following a pre-load stimulus on physical performance measures in handball players.

The purpose of this research was to establish the optimal recovery duration following a pre-load stimulus on performance measures related to handball players. Seventeen senior male University handball players (mean ± SD: age 23.6 ± 2.3 yrs., height 1.79 ± 0.06 m and body mass 72.5 ± 10.7 kg) performed three experimental sessions. All sessions consisted of a standardised warm-up followed by a pre-load stimulus (HSR) back squats followed by a passive rest for either 4-min (PAP4), 8-min (PAP8), or 12-min (PAP12). Following the completion of the passive recovery, players then performed a countermovement jump (CMJ), a 20-m linear sprint and a modified agility t-test. The significance level was set at P < 0.05. There was a significant main effect of passive rest duration after the pre-load stimulus. The PAP12 condition improved CMJ scores (2.3-2.6%; effect size = small), 20-m linear sprint times (3.3-3.7%; effect size = small to moderate) and agility times (1.6-1.9%; effect size = trivial) compared to PAP4 and PAP8 conditions (P < 0.0005). Values of heart rate and rating of perceived exertion were also significantly lower during the PAP12 condition compared to the PAP4 and PAP8 conditions (P < 0.0005). A positive Pearson correlation was established between agility and CMJ for all conditions (P < 0.001). The findings provide novel data observing that a pre-load stimulus, followed by 12-min of recovery, results in greater maximal jump, sprint and agility measures when compared with a 4-min or 8-min recovery in male handball players.

Effect of warm-up and muscle fatiguing exercise on knee joint sounds in motion by vibroarthrography: A randomized crossover trial.

Vibroarthrography measures joint sounds caused by sliding of the joint surfaces over each other. and can be affected by joint health, load and type of movement. Since both warm-up and muscle fatigue lead to local changes in the knee joint (e.g., temperature increase, lubrication of the joint, muscle activation), these may impact knee joint sounds. Therefore, this study investigates the effects of warm-up and muscle fatiguing exercise on knee joint sounds during an activity of daily living. Seventeen healthy, physically active volunteers (25.7 ± 2 years, 7 males) performed a control and an intervention session with a wash-out phase of one week. The control session consisted of sitting on a chair, while the intervention session contained a warm-up (walking on a treadmill) followed by a fatiguing exercise (modified sit-to-stand) protocol. Knee sounds were recorded by vibroarthrography (at the medial tibia plateau and at the patella) at three time points in each session during a sit-to-stand movement. The primary outcome was the mean signal amplitude (MSA, dB). Differences between sessions were determined by repeated measures ANOVA with intra-individual pre-post differences for the warm-up and for the muscle fatigue effect. We found a significant difference for MSA at the medial tibia plateau (intervention: mean 1.51 dB, standard deviation 2.51 dB; control: mean -1.28 dB, SD 2.61 dB; F = 9.5; p = .007; η2 = .37) during extension (from sit to stand) after the warm-up. There was no significant difference for any parameter after the muscle fatiguing exercise (p > .05). The increase in MSA may mostly be explained by an increase in internal knee load and joint friction. However, neuromuscular changes may also have played a role. It appears that the muscle fatiguing exercise has no impact on knee joint sounds in young, active, symptom-free participants during sit to stand.

Reducing the sports injury through function movement biological image data screening / Reduzindo lesões esportivas por meio da triagem de dados biológicos de imagens de movimento / Reducción de las lesiones deportivas mediante la detección de datos biológicos por imágenes en movimiento

ABSTRACT Introduction Among the many cases of sports injuries, the incidence of musculoskeletal injuries remains high. After a musculoskeletal injury occurs, athletes often need to suspend training and undergo rehabilitation. A suitable sport mode requires athletes to have sufficient joint range of motion, core stability, and balance ability in different positions to complete various complex movements in training and competition. Objective The paper analyzes the impact of warm-up exercises before the test on the test results of functional sports biological image data screening ( FMS TM ) and provides references for unifying test conditions, checking the reliability of FMS TM repeated tests, and discussing the comparability of the research results. Methods The paper used the same password and process to test 12 young male volleyball professional athletes without warm-up and warm-up. The two-dimensional motion analysis system Dartfish Pursuit 8.0 was used to analyze the video data recorded by the two cameras simultaneously. Results In the two tests before and after, the hurdle step score (1.75±0.62 vs. 2.42±0.52) and the total score (13.50±2.20 vs. 16.42±2.15) were significantly higher than those without the warm-up test (P<0.01). Besides, in squats (1.58±0.67 vs. 1.92±0.67), straight lunges (2.00±0.43 vs. 2.50±0.52), active straight leg lifts (1.50±0.67 vs. 2.00±0.60), rotation stability (1.42) ±0.52 vs. 1.92±0.29) showed a significant increase in the score (P<0.05). Conclusions Warm-up exercises before the test can improve the test results. This abnormal movement pattern observed only by visual inspection may not truly reflect the "dysfunction" of the movement. In the case of ignoring the pre-test warm-up factors, feedback on sports performance and formulating training strategies, this conclusion of predicting injury risk and evaluating training effects may have specific limitations in its reference value. Level of evidence II; Therapeutic studies - investigation of treatment results.

RESUMO Introdução Dentre os diversos casos de lesões esportivas, a incidência de lesões musculoesqueléticas permanece elevada. Após a ocorrência de uma lesão musculoesquelética, os atletas geralmente precisam suspender o treinamento e se submeter à reabilitação. Um modo de esporte adequado requer que os atletas tenham amplitude de movimento articular suficiente, estabilidade central e capacidade de equilíbrio em diferentes posições para completar vários movimentos complexos em treinamento e competição. Objetivo o artigo analisa o impacto dos exercícios de aquecimento antes do teste sobre os resultados dos testes de triagem de dados de imagens biológicas esportivas funcionais (FMSTM) e fornece referências para unificar as condições de teste, verificar a confiabilidade de testes FMSTM repetidos e discutir a comparabilidade dos resultados da pesquisa . Métodos O artigo utilizou a mesma senha e processo para testar 12 jovens atletas profissionais do sexo masculino de voleibol sem aquecimento e com aquecimento. O sistema de análise de movimento bidimensional Dartfish Pursuit 8.0 foi usado para analisar os dados de vídeo gravados pelas duas câmeras simultaneamente. Resultados Nos dois testes antes e depois, a pontuação do hurdle step (1,75 ± 0,62 vs. 2,42 ± 0,52) e a pontuação total (13,50 ± 2,20 vs. 16,42 ± 2,15) foram significativamente maiores do que aqueles sem o teste de aquecimento ( P <0,01). Além disso, em agachamentos (1,58 ± 0,67 vs. 1,92 ± 0,67), estocadas retas (2,00 ± 0,43 vs. 2,50 ± 0,52), levantamentos ativos de perna reta (1,50 ± 0,67 vs. 2,00 ± 0,60), estabilidade de rotação (1,42) ± 0,52 vs. 1,92 ± 0,29) mostrou um aumento significativo na pontuação (P <0,05). Conclusão Os exercícios de aquecimento antes do teste podem melhorar os resultados do teste. Este padrão de movimento anormal observado apenas por inspeção visual pode não refletir verdadeiramente a "disfunção" do movimento. No caso de ignorar os fatores de aquecimento pré-teste, feedback sobre o desempenho esportivo e formulação de estratégias de treinamento, esta conclusão de prever o risco de lesões e avaliar os efeitos do treinamento pode ter limitações específicas em seu valor de referência. Nível de evidência II; Estudos terapêuticos - investigação dos resultados do tratamento.

RESUMEN Introducción Entre los muchos casos de lesiones deportivas, la incidencia de lesiones musculoesqueléticas sigue siendo alta. Después de que ocurre una lesión musculoesquelética, los atletas a menudo necesitan suspender el entrenamiento y someterse a rehabilitación. Un modo de deporte adecuado requiere que los atletas tengan suficiente rango de movimiento articular, estabilidad central y capacidad de equilibrio en diferentes posiciones para completar varios movimientos complejos en el entrenamiento y la competencia. Objetivo El documento analiza el impacto de los ejercicios de calentamiento antes de la prueba en los resultados de las pruebas de detección de datos de imágenes biológicas deportivas funcionales (FMSTM) y proporciona referencias para unificar las condiciones de prueba, verificar la confiabilidad de las pruebas FMSTM repetidas y discutir la comparabilidad de los resultados de la investigación. Métodos El documento utilizó la misma contraseña y proceso para evaluar a 12 jóvenes atletas profesionales de voleibol sin calentamiento y con calentamiento. El sistema de análisis de movimiento bidimensional Dartfish Pursuit 8.0 se utilizó para analizar los datos de video grabados por las dos cámaras simultáneamente. Resultados En las dos pruebas antes y después, la puntuación del paso de valla (1,75 ± 0,62 frente a 2,42 ± 0,52) y la puntuación total (13,50 ± 2,20 frente a 16,42 ± 2,15) fueron significativamente más altas que aquellas sin la prueba de calentamiento ( P <0,01). Además, en sentadillas (1,58 ± 0,67 vs 1,92 ± 0,67), estocadas rectas (2,00 ± 0,43 vs 2,50 ± 0,52), levantamientos activos de piernas rectas (1,50 ± 0,67 vs 2,00 ± 0,60), estabilidad de rotación (1,42) ± 0,52 vs. 1,92 ± 0,29) mostró un aumento significativo en la puntuación (P <0,05). Conclusión Los ejercicios de calentamiento antes de la prueba pueden mejorar los resultados de la prueba. Este patrón de movimiento anormal observado solo por inspección visual puede no reflejar realmente la "disfunción" del movimiento. En el caso de ignorar los factores de calentamiento previos a la prueba, la retroalimentación sobre el rendimiento deportivo y la formulación de estrategias de entrenamiento, esta conclusión de predecir un riesgo de lesión y evaluar los efectos del entrenamiento puede tener limitaciones específicas en su valor de referencia. Nivel de evidencia II; Estudios terapéuticos: investigación de los resultados del tratamiento.

The Accumulated Effects of Foam Rolling Combined with Stretching on Range of Motion and Physical Performance: A Systematic Review and Meta-Analysis.

Although it is well known that both stretching and foam rolling can acutely increase the range of motion (ROM) and affect performance, the effects of a combined treatment (foam rolling and stretching) are not yet clear. Hence, the purpose of this meta-analysis was to compare the combined effect to that of stretching or foam rolling alone on both ROM and performance. We assessed the effect of a combined treatment on ROM and compared it to the effect of stretching, foam rolling, and a control condition by applying a random-effect meta-analysis. We also applied the same model to compare the effect of the combined treatment on performance. Moreover, by applying a mixed-effect model, we performed subgroup analyses with the stretching technique, type of foam rolling, tested muscles, type of task, and the order of the combined treatment. We found a significant overall effect on ROM change when comparing the combined treatment with the control condition (effect size (ES) = -0.332); however, no significant effect was found when comparing it to stretching (ES = 0.032) or foam rolling alone (ES = -0.225). The meta-analysis revealed no significant overall effect on performance when the combined treatment was compared to stretching alone (ES = -0.029). However, the subgroup analysis for performance revealed a superior effect for the combined treatment compared to stretching alone, but only if foam rolling was followed by stretching (ES = -0.17), and not vice versa. Athletes do not have to combine stretching with foam rolling since no additional effect was observed. However, to increase performance, the combination of foam rolling followed by stretching can lead to greater improvements.

Pre-exercise skin temperature evolution is not related with 100 m front crawl performance.

During the transition between warm-up and competition there is a change in core, muscle and (eventually) skin temperature that may affect swimming performance. We have aimed to assess skin temperature evolution during transition phases of different durations before a typical front crawl effort and to investigate its relationship with performance. Following a standardized warm-up, nine adolescent male swimmers performed three maximal randomized 100 m maximum front crawl trials after 10, 20 and 45 min transition phases. Skin temperature, performance (time, stroke frequency, length and index, and propelling efficiency), heart rate, lactate and perceived effort were assessed. Data showed a skin temperature log increase over time (R2 > 0.96, p < 0.01) without differences from the 15 min with the following instants. Performance and psychophysiological variables were similar between transition phases. However, skin temperature at the end of the transition periods, i.e., just before the 100 m trials, was lower in the 10 min than the 20 and 45 min transitions (32.0 ± 0.6 vs 33.0 ± 0.4 and 33.5 ± 0.5 °C, respectively). The main finding was that no relevant relationships were observed between pre-test skin temperature and performance times (|r| < 0.6, p > 0.05) for the studied transition phases. We have concluded that transitions longer than 10 min will not present thermal changes and that, within the physiologic limits studied, pre-exercise skin temperature does not influence swimming performance.

Effect of the FIFA 11+ soccer specific warm up programme on the incidence of injuries: A cluster-randomised controlled trial.

BACKGROUND: Soccer players incur injuries that typically affect their performance. Injuries are caused by intrinsic and extrinsic factors that call for multifactorial preventive interventions. The study examines the impact of the FIFA 11+ warm up programme on the incidence and severity of injuries in second division soccer players in Rwanda. METHODS: Twelve teams (309 players) were randomised in the intervention group and 12 teams (317 players) in the control group using a cluster randomized controlled trial with teams as the unit of randomization. Intervention group teams implemented the FIFA 11+ soccer specific warm-up programme during training and matches at least three times a week over seven months of the Rwandan soccer season. Control group teams continued with usual warm up exercises. The primary outcome of this study was the overall incidence of training and match injuries. Injuries, training and match exposure as well as severity categories were recorded per the F-MARC guidelines. RESULTS: A lower proportion of players sustained injuries in the intervention group (52%) compared to the control group (63%) (Odd ratio: 0.7; 95%CI: 0.5-0.9). A significantly lower rate ratio was observed in the intervention group for overall (RR = 0.6; 95%CI: 0.5-0.8) and match (RR = 0.6; 95%CI: 0.5-0.8) injuries. Compliance to the injury prevention programme was 77%. In the intervention group, the incidence of injury was similar across all teams and across the medium and highly compliant teams. There was a statistically significant 55% and 71% reduction of the rate of moderate and severe injuries in the intervention group respectively. CONCLUSION: The 11+ warm up injury prevention programme resulted in a significant reduction in the odds of sustaining injuries. In addition, injuries sustained were less severe. The programme should be rolled out to all teams in Rwanda and may well result in a decrease in the incidence and severity of injury in similar contexts. TRIAL REGISTRATION: Pan African Clinical Trial Registry (PACTR201505001045388).

Short and long versions of a 12-week netball specific neuromuscular warm-up improves landing technique in youth netballers.

OBJECTIVE: To investigate the efficacy of two 'NetballSmart', netball specific warm-ups in improving landing technique measures in New Zealand secondary school netball players. DESIGN: Multi-site cluster experimental trial. PARTICIPANTS: 77 youth participants, mean ± SD age = 15.8 ± 0.9 were recruited from secondary school netball teams. SETTING: 12 teams from 6 schools performed either the NetballSmart Dynamic Warm-up (NSDW) (n = 37); or Power warm-up (PWU) (n = 40), three times a week for 12 weeks. All players within a school (2 teams) were assigned the same warm-up, avoiding treatment contamination. MAIN OUTCOME MEASURES: A series of unilateral and bilateral drop vertical jumps on to a portable force plate were completed by all participants. Measures included peak vertical ground reaction force (GRF) for single-leg and bilateral landings; frontal plane projection angle (FPPA) for right and left single-leg landings and Landing error scoring system (LESS) for bilateral landings. Paired t-tests were used to assess mean differences pre and post the warm-up. Generalised linear mixed effects models were developed to evaluate the effects between the NSDW and PWU groups. RESULTS: Significant improvements were found in all the landing technique outcome measures for both warm-up groups (ES Range- GRF = -0.6 to -1.1; FPPA = 0.8 to 1.2; LESS = -1.6 to-3.2; p < 0.05). Results of mixed effects models revealed that there was only a significantly greater improvement in LESS for the PWU group (ß = -0.30, p = 0.001). CONCLUSION: Results show both warm-ups can improve landing technique measures in youth secondary school netball players. It is recommended that coaches should consider implementing one of the two warm-ups in their netball programmes. Their choice of warm-up will likely be dependent on their environment and time demands.