An age-old question in sport is what practice structure yields the best results in relation to effective skill acquisition. This article will define three different practice structures that are referred to as Blocked, Distributed and Random. The answer to this question is critical to all coaches, as they need to structure practices appropriately by selecting technical development drills that are appropriate given the biomotor capabilities of the athletes they are working with, as well as considering such mitigating factors as experience and degree of neuromuscular development. These elements, as well as others, all must be woven into the appropriate tapestry that will lay the foundation for elite athlete development.
Blocked Practice refers to practice where one skill is worked on at a time. This skill is worked on until a predetermined level of competence is acquired, and then the coach and athlete move on to the next skill. One skill may be worked on for several practices before moving on. For example, the curler may work on out-turn line of delivery with draw weight for three consecutive practices before the skill reaches the desired level of proficiency. The decision is then made to move on to the next skill, which might be in-turn line of delivery with draw weight.
Distributed Practice in the literature is often synonymous with Random Practice. However, I prefer to make a clear distinction between the two. I interpret distributed practice as referring to practices where variations of the same skill are worked on in the same workout session. There is, therefore, a commonality in the basic skill being developed; however, variations of that skill might exist in a game situation, and those variations are incorporated into the practice session. Think, for example, of a jump shot in basketball. A blocked practice might have the shot completed 20 times from the same location. In a distributed practice, setting the jump shot would be from as many as 20 different locations, a scenario which might be more consistent with what would happen in a game setting. Therefore the same skill, a jump shot, but with distance variations that require the skill to be adapted to a different condition every time it is executed.
Random Practice refers to practice sessions where multiple skills are incorporated into the same practice session. A predetermined level of competence is not required before moving on to the next skill. In soccer, for example, a random practice might involve time dedicated to individual ball handling skills, followed by passing skills, then heading the ball, and finally specific plays. These multi-tasking types of practices seem to be the most common in the curling environment as in any given practice it is not unusual to see a variety of drills, emphasizing different turns and weights amongst other training variables, incorporated into a single training session.
What coaches need to know is which of these practice formats has been proven through research to be the most effective way for athletes to acquire skills? Are there differences related to age, and therefore the biomotor development levels, of the athlete? What consideration should be given to the experience level of the athlete?
Historically, the random practice format would appear to be the most common practice format as it addresses the immediate concern of repetitive boredom in a practice session, thereby making it easier to keep athletes motivated. In some sports blocked practice sessions are quite common. The long jumper in track and field, for example, might be working only on approaches to the take-off board for several sessions in a row before moving on to take-off mechanics, then flight mechanics, and finally the mechanics associated with effective landings. This would represent an example of blocked practices being used to develop the entire serial sequence of skills required for high level performance. Each part of the skill is developed in the sequence of occurrence until the entire skill is complete. Coaches feel that by dedicating an entire practice to one skill, total focus and therefore deeper and more effective skill acquisition occurs. The desired neuromuscular patterns – more commonly called muscle memory patterns – become entrenched. These types of historical practice patterns alone, however, when supported only by anecdotal evidence do not confirm that random, distributed or blocked practices are the right choice. This can be determined only by empirical evidence that is supported by appropriate and well-structured research.
Not surprisingly, there is not one clear answer but rather the answer is dependent on a variety of factors. In the short term – one month, for example – research has supported that blocked practices are the most effective. Blocked practices also seem to have increased relevance when the performance skill in a competitive situation is always consistent, as the critical motor unit pathways are not dependent on an unpredictable environment. Research, however, does not support this practice structure for longer-term development, or for those sporting situations that have more fluid and unpredictable environments. In these situations research favours distributed and random practice structures as the most effective for skill acquisition.
Both of these practice formats will allow for an athlete to make the more rapid shifts that are common in game situations, meaning skills are more easily transferable from the practice session to the game situation. A variety of skills in an unpredictable order are the real demands of many sports, so practices that can mimic this reality are more effective as the skills become increasingly transferable to the game situation and, as a result, the skills learned tend to be ingrained not only at a more permanent level but more importantly a more flexible level as well, making the skill set a more readily available tool in the athlete’s war chest. This falls in line with the Law of Specificity of Training.
Coaches must be cautious when using blocked practice sessions as too great an emphasis on isolated skill development can easily develop a false sense of confidence in one’s ability level. Consistent success in a specific area with only a few blocked drills may lead the athlete to think that this alone will lead to success in a game situation. However, when other factors come into play in the game environment that are not present in the blocked practice structure, these compounding factors can become confusing since that athlete has not been exposed to them in the practice environment, therefore resulting in compromised performance.
With developmentally young athletes who have little or no skill, then it would seem reasonable that blocked practices would play a more significant role in the skill acquisition process. They may also serve a role at the very beginning of a season in an effort to reset the athlete’s skills after a long period of transition over the summer months. As athletes become more and more competent, then the practice structure should become increasingly distributed and random in nature with a growing emphasis on sessions that mimic game conditions as closely as possible.
Since there appears not to be any research specifically focused on skill acquisition practice structures directly focused on the sport of curling, we are left with analyzing the research done in other sports and then attempt to logically apply that research to the skills required in curling.
An examination of the related skills place curling in a somewhat unique situation, caught somewhere between a traditional individual sport and a traditional team sport. Curling represents a rare team sport where the opposition is relegated to the sidelines to observe and plot potential responses while the other team executes the next play. This is unlike other common team sports where play is influenced by having both teams involved simultaneously in the action, therefore making for more rapid and fluid decision making and skill execution requirements. Basketball or hockey games are excellent examples of team sports where rapidly shifting skills are required to be successful.
Many individual sports, on the other hand, require a very limited number of related skills to be linked together seamlessly to create winning conditions. In these cases the skill set required is, by and large, the same for every competitive situation. An obvious example would be any track and field event.
Curling requires a larger set of skills, such as varied turns, grips and releases and weights – as well as sweeping – than is commonly found in most individual sports, suggesting that skill acquisition might best be in line with practice patterns suited for team sports. However, unlike team sports these skills are carried in an environment that is to a greater degree fixed and stable as the skill is being applied – therefore resembling the conditions that most individual sports are accustomed to. These conditions remove, to a large degree, the need for rapid decision making and skill execution that is common in traditional team sports and suggest that skill acquisition might best be addressed using practice formats that are consistent with patterns used in individual sports.
Given this dichotomy, reason would suggest that the answer lies in the middle ground. The following chart outlines a balance that could be considered between Blocked, Distributed and Random Practices at varying stages of athletic development.
What this chart suggests falls in line with skill acquisition research, suggesting that developmental athletes focus on the blocked practice approach and, as athletes progress, distributed and random practices should play a larger and more consistent role in practice sessions.
 C.I. Karageorghis and P. Terry. Inside Sport Psychology. Human Kinetics, 2011.
 T. Weir. Distributed Versus Blocked Practice.
 D.L. Wright. Manipulating generalized motor program difficulty during blocked and random practice does not affect parameter learning. Research quarterly for exercise and sport, 2001. US National Center for Biotechnology Information.