The Validity of Perceived Recovery Status as a Marker of Daily Recovery Following a High-Volume Back-Squat Protocol.

Although a variety of tools to monitor recovery have been developed, many are impractical for daily use due to cost, time, and challenges with interpretation. The Perceived Recovery Status (PRS) scale was recently developed as an expeditious, noninvasive tool to assess recovery status. While PRS has been strongly associated with repeated sprinting performance, a paucity of research exists relating PRS and performance recovery following resistance exercise. PURPOSE: The purpose of this study was to evaluate the sensitivity of PRS as a subjective marker of recovery up to 72 hours after a high-volume back-squat protocol. METHODS: Eleven resistance-trained men reported to the laboratory on 5 separate occasions (1 familiarization session and 4 testing sessions). The first testing session was considered the baseline session and consisted of a nonfatiguing performance assessment (ie, countermovement jumps and back squats) and a fatiguing back-squat protocol of 8 sets of 10 at 70% 1-repetition maximum separated by 2 minutes of recovery. Participants returned 24, 48, and 72 hours following baseline to provide a PRS rating and complete the performance assessment. RESULTS: Repeated-measures correlations revealed strong associations between PRS countermovement jump (r = .84) and mean bar velocity (r = .80) (both P < .001). CONCLUSIONS: The current findings suggest that PRS can be used as a method to effectively assess daily recovery following a fatiguing bout of resistance exercise. Practitioners are cautioned that the relationship between PRS and performance recovery is individualized, and equivalent PRS scores between individuals are not indicative of similar recovery.

Mouth Rinsing Cabohydrates Serially Does Not Improve Repeated Sprint Time.

Sensing carbohydrates via the oral cavity benefits performance outcomes during brief high intensity bouts of exercise. However, the extent to which carbohydrates need to be present in the oral cavity to influence sprint performance is less understood. The purpose of this study was to determine if serial increases in carbohydrate rinse time across sprint sets attenuates increases in sprint time compared to no serial increases in carbohydrate rinse time across sprint sets. Fifteen sprint trained participants completed three repeated anaerobic sprint tests (RAST), 3 sets of 6 x 35-m sprints, under two different carbohydrate mouth rinsing (CMR) conditions; (1) rinsing for only 5 seconds (s), and (2) rinsing for 5 s, 10 s and 15 s (serial rinse). Prior to a RAST, participants provided perceived recovery status (PRS) and perceived feeling of arousal (FAS). Upon completion of each individual sprint, participants gave a rating of perceived exertion (RPE). A lactate sample was taken upon completion of each individual sprint set and after all 3 RASTs a session rating of perceived exertion (S-RPE) was measured. There were no significant differences in peak (p = 0.18) and average sprint time (p = 0.41). There were no significant differences in perceptual measures: RPE, PRS, FAS, S-RPE or for blood lactate concentration between CMR conditions. Overall, serial rinsing resulted in changes that were most likely trivial, but showed a 50% chance in perceiving a sprint session as less difficult. Rinsing carbohydrates in a serial manner between repeated sprint sets produces trivial changes of sprint speed and perceptual measures from sprint performance.

Differentiated ratings of perceived exertion between overweight and non-overweight children during submaximal cycling.

OBJECTIVE: Few studies have examined differences in ratings of perceived exertion (RPE) between overweight (OW) and non-OW (NW) youth. With lower voluntary participation in physical activity in OW children, it seems plausible that these youth may experience elevated RPE. Therefore, this study compared RPE during two separate steady-state cycling bouts OW (>95th body mass index [BMI] percentile) and NW (<90th BMI percentile) children. METHODS: Participants completed one of two 20-min cycling trials; one performed at 70% age-predicted peak heart rate (HR) (70%) (OW n = 12 and NW n = 21) and a self-selected intensity (SS) (OW n = 6 and NW n = 13) with RPE overall, RPE legs (RPE-L), and RPE chest estimated at 5, 10, 15, and 20 min. RESULTS: A repeated measures ANOVA revealed that OW individuals had significantly lower RPE-L values at 5, 15, and 20 min during the SS trial. No significant differences were identified during the 70% trial. CONCLUSIONS: OW youth do not perceive cycling at 70% age-predicted peak HR or at SS intensities more difficult than NW children. It may be that cycling could serve as an attractive mode to encourage physical activity in this population and perhaps increase self-efficacy of exercise in this population.

A Comparison of Both Motorized and Nonmotorized Treadmill Gait Kinematics to Overground Locomotion.

CONTEXT: Motorized treadmills (MTs) present an altered motor task compared to overground (OG) locomotion in that MT belt surfaces are motor-driven, whereas individuals walking/running OG must propel themselves. A possible solution may lie with novel nonmotorized treadmill (NMT) devices as the belt surface is propelled by the user. OBJECTIVE: The purpose of this study was to compare gait performance during both MT and NMT locomotion to OG. DESIGN: Crossover study. SETTING: A university research laboratory. PATIENTS: A total of 20 healthy adults (10 women) participated in the study. INTERVENTION: Each participant performed self-selected walking and running OG, and on both an MT and NMT. MAIN OUTCOME MEASURE: Shoulder, trunk, and lower-extremity kinematics were analyzed for each treadmill condition and compared to OG. RESULTS: The analyses demonstrated that there were no differences between MT and OG gait kinematics during either walking or running. However, NMT gait showed increased hip, knee, and ankle flexions in late swing and early stance compared to OG during both walking and running. For example, during walking, the NMT elicited hip-, knee-, and ankle-flexion/extension angles of 34.7°, 8.0°, and 3.6° at foot strike compared to 24.8°, -3.1°, and -5.8° in the OG condition (P < .05). There was also a significant reduction in trunk-flexion/extension range of motion during running compared to OG (7.7° in NMT vs 9.8° in OG). CONCLUSIONS: These differences may have implications for both training and rehabilitation on an NMT. Future studies should consider the influence of NMT familiarization on gait performance and should emphasize the assessment of neuromuscular performance.

Comparison of V[Combining Dot Above]O2peak Performance on a Motorized vs. a Nonmotorized Treadmill.

Morgan, AL, Laurent, CM, and Fullenkamp, AM. Comparison of V[Combining Dot Above]O2peak performance on a motorized vs. a nonmotorized treadmill. J Strength Cond Res 30(7): 1898-1905, 2016-Despite growing popularity of nonmotorized treadmills (NMTs), little data exist regarding responses during exercise testing using this equipment, which is important when providing an appropriate exercise prescription. The purpose of this study was to evaluate physiological and perceptual responses during peak graded exercise tests (GXTs) on a motorized treadmill (MT) vs. NMT. Volunteers (12 men and 12 women aged 18-35 years) performed 2 peak GXT sessions (1 MT and 1 NMT). Respiratory gases and heart rate (HR) were collected each minute; perceptual response was estimated (Borg's 6-20 rating of perceived exertion [RPE] scale) during the final 10 seconds of each stage. Peak values (i.e., V[Combining Dot Above]O2, HR, speed) were determined during the final 10 seconds of each test; ventilatory threshold (VT) was assessed using the V-slope method. Paired t-tests matching variables measured at each stage of the GXT identified significantly higher values on the NMT for V[Combining Dot Above]O2 83% of the time, HR 67% of the time, and RPE 25% of the time. Interestingly though, neither peak V[Combining Dot Above]O2 (48.6 ± 9.2 ml·kg·min vs. 47.8 ± 8.9 ml·kg·min), peak HR (185 ± 9 b·min vs. 188 ± 10 b·min; p = 0.90), nor VT (72.7 ± 5.7% vs. 73.8 ± 5.4%) were significantly different on the NMT vs. the MT. However, significant differences were identified between NMT and MT tests for time to exhaustion (9:55 ± 1:49 vs. 12:05 ± 2:48; p < 0.01) and peak speed (8.0 ± 0.9 mph vs. 9.2 ± 1.4 mph; p < 0.01). Thus, although peak values obtained were similar between testing sessions on the NMT and MT, the majority of submaximal data were significantly different between trials. These differences are important when designing exercise prescriptions using submaximal values from NMT testing that may be inappropriately high or low at corresponding intensities during training.

Pain-Coping Traits of Nontraditional Women Athletes: Relevance to Optimal Treatment and Rehabilitation.

CONTEXT: The primary goal of traditional treatment and rehabilitation programs is to safely return athletes to full functional capacity. Nontraditional activities such as rock climbing or rodeo are typically less training structured and coach structured; individualism, self-determination, and autonomy are more prevalent than observed in athletes in National Collegiate Athletic Association (NCAA)-sponsored sports. The limited research available on nontraditional athletes has provided the athletic trainer little insight into the coping skills and adaptations to stressors that these athletes may bring into the clinical setting, especially among the growing number of women participating in these types of activities. A better understanding of the pain-coping traits of nontraditional competitors would enhance insight and triage procedures while heading off potential athlete-related risk factors in the clinical setting. OBJECTIVE: To quantify and compare pain-coping traits among individual-sport women athletes participating in nontraditional versus traditional NCAA-structured competition, with relevance to optimal treatment and rehabilitation. DESIGN: Cross-sectional study. SETTING: Data collected during each participant's respective group meeting before seasonal activity. Participants or Other Participants : A total of 298 athletes involved in either nontraditional, non-NCAA individual sports (n = 152; mean age = 20.2 ± 1.3 years; downhill skiing, martial arts, rock climbing, rodeo, skydiving, telemark skiing) or traditional NCAA sports (n = 146; mean age = 20.3 ± 1.4 years; equestrian, golf, swimming/diving, tennis, track). MAIN OUTCOME MEASURE(S): All participants completed the Sports Inventory for Pain, a sport-specific, self-report instrument that measures pain-coping traits relevant to competition, treatment, and rehabilitation. Trait measures were direct coping, cognitive, catastrophizing, avoidance, body awareness, and total coping response. Data were grouped for analyses by type of athlete (nontraditional, traditional). RESULTS: We found a significant main effect for type of athlete (Wilks' λ F6,291 = 12.922; P = .0001). Nontraditional sport athletes scored lower on direct coping (P = .0001), cognitive (P = .0001), catastrophizing (P = .0001), and total coping response (P = .0001) than traditional athletes. CONCLUSIONS: Women participating in nontraditional individual-sport activity revealed less pronounced pain-coping traits than women participating in more coach-structured, traditional NCAA sports. Sport and medical personnel should consider the type of athlete when prescribing training, treatment, and rehabilitation for optimal performance and return to play.

The Contribution of Trunk Axial Kinematics to Poststrike Ball Velocity During Maximal Instep Soccer Kicking.

To date, biomechanical analyses of soccer kicking have focused predominantly on lower-extremity motions, with little emphasis on the trunk and upper body. The purpose of this study was to evaluate differences in trunk axial kinematics between novice (n = 10) and skilled (n = 10) participants, as well as to establish the relationship of trunk axial motion and sagittal plane thigh rotation to poststrike ball velocity. Three-dimensional body segmental motion data were captured using high-resolution motion analysis (120 Hz) while each participant completed 5 maximal instep soccer-style kicks. The results demonstrate that skilled participants use 53% greater axial trunk range of motion compared with novice participants (P < .01), as well as 62% greater peak trunk rotation velocity (P < .01). The results also show a moderate, positive correlation of peak trunk rotation velocity with poststrike ball velocity (r = .57; P < .01), and peak hip flexion velocity with poststrike ball velocity (r = .63; P < .01). The current study highlights the potential for trunk rotation-specific training to improve maximum instep kick velocity in developing soccer athletes.

Placebo Effect: Influence on Repeated Intermittent Sprint Performance on Consecutive Days.

Despite the available literature addressing the placebo effect's role in mediating human performance, there is a paucity of research addressing the possibility of a placebo effect both within and between bouts of repeated sprint performance on consecutive days. Therefore, the purpose of this study was to determine whether the administration of a placebo influences recovery during sessions of intermittent sprinting. Ten subjects performed 4 repeated sprint tests under 2 different conditions; 2 while being administered a control beverage separated by 24 hours of recovery and the other 2 with a placebo beverage separated by 24 hours of recovery. Before each sprint test, subjects provided perceived recovery status (PRS). Ratings of perceived exertion were recorded within 5 seconds after each sprint. After each repeated sprint protocol, subjects were asked to provide a rating of perceived exertion (RPE), rate their pain, and provided a blood lactate sample. Power was recorded throughout each session from a nonmotorized treadmill to analyze changes in sprinting performance. Repeated-measures analysis of variance was used to determine significant differences in peak and mean power, PRS, RPE, pain, and blood lactate. The placebo trial produced significantly higher peak (p < 0.001) and mean power (p = 0.002) vs. the control in later sprints absent of any other significant difference in metabolic or perceptual strain (p > 0.05). In conclusion, it seems that the administration of a placebo can attenuate the decline in performance as fatigue increases during repeated sprinting bouts.

Power, fatigue, and recovery changes in national collegiate athletic association division I hockey players across a competitive season.

This study aimed to evaluate changes in pre- to postseason power output, fatigue, and recovery during a repeated sprint test. Twenty National Collegiate Athletic Association Division I men's hockey athletes performed identical sessions of repeated sprint work pre- and postseason. The repeated sprint test consisted of 5 sets of 45 seconds of repeated sprint work with 90 seconds of rest in between each series of sprints. Power output (W), decrement, and recovery scores (RECs) were determined using raw data from a nonmotorized treadmill. Ratings of perceived exertion were recorded after, and perceived readiness (PR) recorded before, each series of sprints. Mean power was significantly higher in preseason vs. postseason performance during sprint 1 (760.6 vs. 691.3 W; p = 0.03), sprint 2 (719.9 vs 657.0 W; p = 0.05), sprint 4 (648.4 vs 588.9 W; p = 0.04), and sprint 5 (656.6 vs. 586.8 W, p = 0.04). Ratings of perceived exertion were significantly higher during sprints 3, 4, and 5 postseason with PR significantly higher (indicating less readiness) before sprints 3 and 4. There were no significant differences in REC or decrement score. Overall, athletes were unable to maintain power during subsequent repeated sprint work during postseason. The degree to which the athletes fatigued and recovered between sprints did not change between pre- and postseason testing, however, athletes exhibit increased perceptual strain during the repeated sprint work. These data indicate meaningful performance and perceptual differences throughout the competitive season in collegiate-level hockey players.

Sex-specific responses to self-paced, high-intensity interval training with variable recovery periods.

This study examined sex-specific responses during self-paced, high-intensity interval training (HIIT). Sixteen (8 men and 8 women) individuals completed a peak oxygen uptake test and 3 treadmill HIIT sessions on separate days. The HIIT sessions consisted of six 4-minute intervals performed at the highest self-selected intensity individuals felt they could maintain. Recovery between intervals was counterbalanced and consisted of 1-, 2-, or 4-minute recovery during each trial. Relative measures of intensity, including percentage of velocity at VO2peak (vVO2peak), %VO2peak, %HRmax, and blood lactate concentration ([La]), were observed during the trials. Perceived readiness was recorded immediately before and ratings of perceived exertion (RPE) were recorded at the end of each interval with session RPE recorded after each trial. Results revealed a significant effect of sex on %vVO2peak (p < 0.01) and %HRmax (p < 0.01). Data show that across trials, men self-select higher %vVO2peak (84.5 vs. 80.7%), whereas women produce higher %HRmax (96.9 vs. 92.1%) and %VO2peak (89.6 vs. 86.1%) with no difference in [La] or perceptual responses. These findings support the notion that women may demonstrate improved recovery during high-intensity exercise, as they will self-select intensities resulting in greater cardiovascular strain. Moreover, results confirm previous findings suggesting that a 2:1 work-to-rest ratio is optimal during HIIT for both men and women.

Changes in perceived recovery status scale following high-volume muscle damaging resistance exercise.

Currently no research has investigated the relationship between muscle damage, hormonal status, and perceived recovery scale (PRS). Therefore, the purpose of this study was to determine the effects of a high-volume training session on PRS and to determine the relationship between levels of testosterone, cortisol, and creatine kinase (CK) and PRS. Thirty-five trained subjects (21.3 ± 1.9 years) were recruited. All subjects participated in a high-volume resistance training session consisting of 3 sets of full squats, bench press, deadlifts, pullups, dips, bent over rows, shoulder press, and barbell curls and extensions. Pre-PRS and post-PRS measurements (0-10), soreness, CK, cortisol, and testosterone were measured before and 48 hours after training. Perceived recovery scale declined from 8.6 ± 2.3 to 4.2 ± 1.85 (p < 0.05). Leg, chest, and arm soreness increased from pre- to postexercise. Creatine kinase significantly increased from pre- to postworkout (189.4 ± 100.2 to 512 ± 222.7 U/L). Cortisol, testosterone, and free testosterone did not change. There was an inverse relationship between CK and PRS (r = 0.58, p < 0.05). When muscle damage was low before training, cortisol and free and total testosterone were not correlated to PRS. However, when damage peaked at 48 hours postexercise, free, but not total, testosterone showed a low direct relationship with PRS (r = 0.2, p < 0.05). High-volume resistance exercise lowers PRS scores. These changes are partly explained by a rise in serum indices of muscle damage. Moreover, free testosterone seems to have a positive relationship with PRS.

A practical approach to monitoring recovery: development of a perceived recovery status scale.

The aim of this study was to develop and test the practical utility of a perceived recovery status (PRS) scale. Sixteen volunteers (8 men, 8 women) performed 4 bouts of high-intensity intermittent sprint exercise. After completion of the baseline trial, in a repeated-measures design, subjects were given variable counterbalanced recovery periods of 24, 48, and 72 hours whereupon they repeated an identical intermittent exercise protocol. After a warm-up period, but before beginning each subsequent bout of intermittent sprinting, each individual provided their perceived level of recovery with a newly developed PRS scale. Similar to perceived exertion during exercise, PRS was based on subjective feelings. The utility of the PRS scale was assessed by measuring the level of agreement of an individual's perceived recovery relative to their performance during the exercise bout. Perceived recovery status and change (both positive and negative) in sprint performance during multiple bouts of repeated sprint exercise were moderately negative correlated (r = -0.63). Additionally, subjects were able to accurately assess level of recovery using the PRS scale indicated by correspondence with negative and positive changes in total sprint time relative to their previous session. The ability to detect changes in performance using a noninvasive psychobiological tool to identify differences in performance was independent of other psychological and physiological markers measured during testing, because there were no differences (p > 0.05) among ratings of perceived exertion (RPE), heart rate, blood lactate concentration, or session RPE values among any of the performance trials. Although further study is needed, current results indicate a subjective approach may be an effective means for assessing recovery from day to day, at least under similar conditions.

The rodeo athlete: injuries - Part II.

A previous instalment to this review focused on the sport science for rodeo, the history behind the sport and what is currently known about the physical and physiological status, coronary risk profile, strength and power levels, event-specific kinesiological and biomechanical aspects, nutritional habits and psychological indices associated with the rodeo athlete. In regards to injury, rodeo is well known for its high-velocity, high-impact atmosphere where athletes compete against the clock and uncooperative livestock. Considered by many to be a dangerous sport with high vulnerability towards trauma and frequent injuries, animal/human contact events comprise ∼80% of reported injuries. Severe trauma includes fractures, dislocations, subluxations, concussions, ligament ruptures, pneumothorax and various neurapraxias. Head and neck trauma account for 10-29% of total trauma and up to 63% of upper body injuries, with concussion incidence rates of 3.4 per 1000 competitive exposures. The incidence of thoracic, back and abdominal injuries comprise 11-84% of trauma, while shoulder injuries, involving anterior/posterior arthralgia, inflammation, instability and increasing weakness, account for 8-15% of upper extremity cases. Lower extremity trauma accounts for 26-34% of cases, with the majority involving the knee. Many believe that the incidence of trauma is underestimated, with studies hampered by numerous limitations such as a lack of injury awareness, missing data, poor injury recall, an array of reporting sources, delays in subject response and treatment, no uniform definition of injury or reporting system and predisposing factors prior to injury. Primary mechanisms of injuries are attributed to physical immaturity, fatigue, age and experience, behaviour, the violent nature of the sport and lack of adequate medical intervention. Although there is limited adherence to organized conditioning programmes, when properly planned, sport-specific conditioning may enhance athletic potential, minimize predisposition to injury and enhance recovery. Education in care and rehabilitation should be spearheaded by the medical community to reduce injury, as several studies have linked trauma to poor technique, inexperience and poor judgement. Medical services should encompass emergency medical oversight for trauma at all levels and press toward preventive care. Competitors should also be cognizant of the signs and symptoms of overtraining, a condition exacerbated by overuse and minimal recovery. The use of helmets, taping, bracing, protective vests, cervical collars and mouthpieces is gaining popularity but has not been thoroughly studied. Guidelines requiring padding of chutes, gates or equipment essential for performance may also avert trauma. Whether increases in knowledge, education and technology are able to reduce predisposition to injury among this population, remains to be seen. As with all high-risk sports, the answer may lie in increased wisdom and responsibility of coaches and athletes to ensure an adequate level of ability, self-control and common sense as they compete in this sport.

The rodeo athlete: sport science: part I.

Based on the tradition, history and lore of the American West, as well as the individualistic nature and lifestyle of the sport of rodeo, the rodeo athlete has achieved iconic status in sport, literature, art and entertainment. For over half a century, rodeo has become a staple of organized sport programmes in high schools, universities and international competitions. The origins of rodeo grew from ranch work dating back to the Spanish vaqueros in the 1700s. The sport was officially organized in 1929 and, by the 1930s, championships were determined and the sport of rodeo surpassed baseball and auto racing in spectator attendance. Since then, sponsorship has grown, resulting in extensive worldwide popularity through major media outlets. Despite growing popularity, few investigations exist regarding the scientific aspects of the sport. Rodeo competition is an activity that is basically intermittent in nature, with short periods of highly intense activity. When considering that experience and, thus, improvement in rodeo is achieved solely through constant and punishing practices involving actual and repetitive, human versus livestock competition, the practices closely imitate a sport-specific form of interval training. Studies, which address the anthropometric and performance characteristics of rodeo competitors, reveal that they are comparable to athletes in more traditional sports. The psychological constructs conducive to performance in rodeo have been varied and limited, with most research efforts focused on personality characteristics, sensation seeking and competitive anxiety. Nevertheless, when evaluated relative to higher levels of traditional sport performance, rodeo participants closely resemble their mainstream counterparts. Although efforts to quantify this non-traditional sport are still in the initial stages, information concerning what the optimal fitness level of rodeo athletes should be for maximal performance levels, in a basically anaerobic sport, remains to be determined and is an area for future study. Rodeo performance, as with all sports, is based on a multifactorial array of variables and, therefore, interdisciplinary efforts encompassing expertise across medicine, science and coaching are encouraged. Taking a comprehensive approach in the assessment of athletes, as well as the development and quantification of event-specific training protocols, may ultimately enhance athletic potential, minimize opportunity for injury and possibly provide information to coaches and allied health professionals for the appropriate development and optimal medical care of these athletes.

Multiple Models Can Concurrently Explain Fatigue During Human Performance.

One of the most commonly and thoroughly studied paradigms of human performance is fatigue. However, despite volumes of research there remains considerable controversy among scientists regarding definitive conclusions about the specific mechanism(s) contributing to fatigue. Within the literature there are three primary yet distinctly different governing ideas of fatigue; the traditionally referenced central model and peripheral model as well as the emerging central governor model (CGM). The CGM has recently been advocated by a limited number of researchers and is suggestive of a more integrative model of fatigue when compared the traditional peripheral and central models. However, more work is needed to determine the specific and perhaps synergistic roles of each paradigm during exercise or sport activity. This article contains three components; (1) a brief overview of the problems associated with defining fatigue, (2) a description of the models governing interpretation of fatigue and, (3) a presentation of multiple interpretations of selected data to demonstrate that some results can be reasonably explained using multiple models of fatigue, often concurrently. The purposes of this paper are to reveal that a) perhaps it is not the results that suggest a certain paradigm of regulation, yet that it may be a product of an a priori definition that is being employed and b) an integrative model of central and peripheral fatigue may present a plausible explanation for fatigue vs. adherence to the notion that each paradigm is mutually exclusive.

Validity of the VmaxST portable metabolic measurement system.

The aim of this study was to assess and compare the validity of the portable VmaxST telemetry metabolic measurement device with that of a standard measurement system (Vmax29). Thirty asymptomatic, moderately active males provided written, informed consent and completed two maximal graded treadmill exercise tests (Bruce) using the VmaxST and the Vmax29 metabolic measurement systems. Tests were performed in random order on separate days to obtain peak values for time to exhaustion, heart rate, systolic and diastolic blood pressure, oxygen consumption (VO2), carbon dioxide production (VCO2), ventilation (VE), and respiratory exchange ratio (RER). Multivariate analysis of variance revealed no significant main effect (P = 0.88) between the two systems across any variable, suggesting similar measurement capabilities between the two systems. Linear regression analyses revealed moderate to high coefficients of determination for VO2 (r2 = 0.99), VCO2 (r2 = 0.99), VE r2 = 0.99), and RER (r2 = 0.89). Furthermore, Bland-Altman analyses demonstrated that the VmaxST yielded similar values to the Vmax29, suggesting good agreement between the two systems. Agreement was confirmed when the differences between the methods resulted in a small range as identified by the 95% limits of agreement. Findings from the current study confirm that the VmaxST is a valid device for measuring metabolic and physiological variables during exercise within a controlled laboratory setting.

Downhill ski injuries in children and adolescents.

Downhill skiing is considered to be an enjoyable activity for children and adolescents, but it is not without its risks and injuries. Injury rates now range between 3.9 and 9.1 injuries per 1000 skier days, and there has been a well documented increase in the number of trauma cases and fatalities associated with this sport. Head and neck injuries are considered the primary cause of fatal injuries and constitute 11-20% of total injuries among children and adolescents. Cranial trauma is responsible for up to 54% of total hospital injuries and 67% of all fatalities, whereas thoracoabdominal and spine injuries comprise 4-10% of fatalities. Furthermore, there has been an increase in the proportion of upper extremity trauma with acromioclavicular dislocations, and clavicle and humeral fractures accounting for the majority (22-79%) of the injuries. However, the most common and potentially serious injuries in children and adolescents are those to the lower extremity, with knee sprains and anterior cruciate ligament tears accounting for up to 47.7% of total injuries. Knee sprains and grade III ligament trauma associated with lower leg fractures account for 39-77% of ski injuries in this young population. Approximately 15% of downhill skiing injuries among children and adolescents are caused by musculoskeletal immaturity. Other factors include excessive fatigue, age, level of experience, and inappropriate or improperly adjusted equipment. Collisions and falls constitute a significant portion (up to 76%) of trauma, and are commonly associated with excessive speed, adverse slope conditions, overconfidence leading to carelessness, and behavioural patterns within and among gender. The type and severity of injuries are typically functions of biomechanical efficiency, skiing velocity or slope conditions; however, a multiplicative array of intrinsic and extrinsic factors may simultaneously be involved. Despite extensive efforts to provide a comprehensive picture of the aetiology of injury, limitations have hampered reporting. These limitations include age and injury awareness, data collection challenges, lack of uniformity in the definition or delineation of age classification and lack of knowledge of predisposing factors prior to injury. Since skill level is the primary impetus in minimising ski injuries, formal instruction focusing on strategies such as collision avoidance and helmet use, fall training minimising lower extremity trauma, altering ski technique and avoiding behaviours that lead to excessive risk are, therefore, highly recommended. Skiing equipment should be outfitted to match the young skier's height, weight, level of experience, boot size and slope conditions. Additionally, particular attention should be paid to slope management (i.e. overcrowding, trail and obstacle marker upkeep) and minimising any opportunity for excessive speed where children are present. Whether increases in knowledge, education and technology will reduce predisposition to injury among this population remains to be seen. As with all high-risk sports, the answer may lie in increased wisdom and responsibility of both the skier and the parent to ensure an adequate level of ability, self-control and simply common sense as they venture out on the slopes.

Cross-validation of the 20- versus 30-s Wingate anaerobic test.

The 30-s Wingate anaerobic test (30-WAT) is the most widely accepted protocol for measuring anaerobic response, despite documented physical side effects. Abbreviation of the 30-WAT without loss of data could enhance subject compliance while maintaining test applicability. The intent of this study was to quantify the validity of the 20-s Wingate anaerobic test (20-WAT) versus the traditional 30-WAT. Fifty males (mean +/- SEM; age = 20.5 +/- 0.3 years; Ht = 1.6 +/- 0.01 m; Wt = 75.5 +/- 2.6 kg) were randomly selected to either a validation (N = 35) or cross-validation group (N = 15) and completed a 20-WAT and 30-WAT in double blind, random order on separate days to determine peak power (PP; W kg(-1)), mean power (MP; W kg(-1)), and fatigue index (FI; %). Utilizing power outputs (relative to body mass) recorded during each second of both protocols, a non-linear regression equation (Y (20WAT+10 )= 31.4697 e(-0.5)[ln(X (second)/1174.3961)/2.6369(2)]; r (2) = 0.97; SEE = 0.56 W kg(-1)) successfully predicted (error approximately 10%) the final 10 s of power outputs in the cross-validation population. There were no significant differences between MP and FI between the 20-WAT that included the predicted 10 s of power outputs (20-WAT+10) and the 30-WAT. When derived data were subjected to Bland-Altman analyses, the majority of plots (93%) fell within the limits of agreement (+/-2SD). Therefore, when compared to the 30-WAT, the 20-WAT may be considered a valid alternative when used with the predictive non-linear regression equation to derive the final power output values.