Background: In team handball an anterior cruciate ligament (ACL) injury often occurs during landing after a jump shot. Many intervention programs try to reduce the injury rate by instructing the athletes to land safer. Video feedback is an effective way to provide feedback although little is known about its influence on landing technique in sport-specific situations. Objective: To test the effectiveness of a video overlay feedback method on landing technique in elite handball players. Method: Sixteen elite female handball players were assigned to a Control or Video Group. Both groups performed jump shots in a pre-test, two training sessions (TR1 & TR2) and a post-test. The Video Group received video feedback of an expert model with an overlay of their own jump shots in TR1 and TR2 whilst the Control Group did not. Main outcome measures were sagittal ankle, knee and hip angles during initial contact (IC), maximum (MAX) and range of motion (ROM), in addition to the Landing Error Scoring System (LESS) score. One 2x4 repeated measures ANOVA was conducted to analyze group, time and interaction effects of all kinematic outcome measures and the LESS score. Results: The Video Group displayed significant improvement in knee and hip flexion at IC, MAX and ROM. In addition, MAX ankle flexion and their LESS score improved an average of 8.1 in the pre-test to 4.0 in the post-test. When considering performance variables, no differences between Control Group and Video Group were found in shot accuracy or vertical jump height, whilst horizontal jump distance in the Video Group became greater over time. Conclusion: Overlay visual feedback is an effective method to improve landing kinematics during a sport-specific jump shot. Further research is now warranted to determine the long-term effects and transfer to training and game situations.
Uit onderzoek blijkt de kwaliteit van de leraar voor de klas de meest belangrijke factor is op het leerresultaat van leerlingen.Leraarschap is een professie en net als andere professionals moeten leraren hun vak bijhouden en constant hun eigen handelen evalueren en verbeteren. Soms gaat dat vanzelf, bijvoorbeeld bij beginnende leraren. Om te overleven, zijn zij gedwongen heel snel te leren en zich verder te ontwikkelen. Maar meer ervaren leraren hebben inmiddels allerlei routines opgebouwd en missen vaak wat Koffeman (2011) noemt de 'noodzaak tot leren'. Het proefschrift beschrijft mogelijkheden om de professionalisering van leraren te stimuleren door middel van reflectiegesprekken met collega's en het gebruik van videofeedback. Het proefschrift betreft een ontwerponderzoek met als doel: op onderzoek gebaseerde oplossingen te ontwikkelen voor complexe problemen uit de onderwijspraktijk en tevens bij te dragen aan wetenschappelijke theorievorming, door het bestuderen van de onderliggende ontwerpprincipes. Samen met een school voor voortgezet onderwijs is een concreet programma ontworpen dat meer informele vormen van leren op de werkplek tussen leraren stimuleert. Door het ontwerpproces en de uitkomsten stap voor stap te beschrijven, levert dit onderzoek niet alleen een kant-en-klaar professionaliseringsprogramma dat andere scholen kunnen gaan gebruiken, maar levert het vooral ook bouwstenen op in de vorm van ontwerpprincipes en kennis over hoe en onder welke voorwaarden deze in de school kunnen werken. Met deze bouwstenen worden ook andere scholen in staat gesteld om het programma aan te passen aan de context van de eigen school.
Background: This follow-up study investigated the year-round effects of a four-week randomized controlled trial using different types of feedback on employees’ physical activity, including a need-supportive coach intervention. Methods: Participants (n=227) were randomly assigned to a Minimal Intervention Group (MIG; no feedback), a Pedometer Group (PG; feedback on daily steps only), a Display Group (DG; feedback on daily steps, on daily moderateto-vigorous physical activity [MVPA] and on total energy expenditure [EE]), or a Coaching Group (CoachG; same as DG with need supportive coaching). Daily physical activity level (PAL; Metabolic Equivalent of Task [MET]), number of daily steps, daily minutes of moderate to vigorous physical activity (MVPA), active daily EE (EE>3 METs) and total daily EE were measured at five time points: before the start of the 4-week intervention, one week after the intervention, and 3, 6, and 12 months after the intervention. Results: For minutes of MVPA, MIG showed higher mean change scores compared with the DG. For steps and daily minutes of MVPA, significantly lower mean change scores emerged for MIG compared with the PG. Participants of the CoachG showed significantly higher change scores in PAL, steps, minutes of MVPA, active EE, total EE compared with the MIG. As hypothesized, participants of the CoachG had significantly higher mean change scores in PAL and total EE compared with groups that only received feedback. However, no significant differences were found for steps, minutes of MVPA and active EE between CoachG and PG. Conclusions: Receiving additional need-supportive coaching resulted in a higher PAL and active EE compared with measurement (display) feedback only. These findings suggest to combine feedback on physical activity with personal coaching in order to facilitate long-term behavioral change. When it comes to increasing steps, minutes of MVPA or active EE, a pedometer constitutes a sufficient tool. Trial registration: Clinical Trails.gov NCT01432327. Date registered: 12 September 2011
