Is praying the Catholic rosary a meditation and does it enhance brain plasticity? Futurism.com says that meditation can shape brains and increase brain plasticity and fit. Can we say that praying the Catholic rosary is a kind of meditation and does this prayer have all the benefits of meditation?

The common practice of the rosary is to say five decades a day each containing an Our Father and ten Hail Marys keeping one's place with a looped string of beads. All Catholics know these prayers by heart and can repeat them almost automatically, so thoughts are directed towards some inner prayer and talk with God during its recital. 

Is this a kind of meditation and does it enhance brain plasticity?
The accepted method of praying the Rosary is to actually complete five (5) decades, each containing the Hail Mary (Ave Maria) repeated 10 times (hence the term "decade"). Each decade is followed by an Our Father (Pater Noster), Gloria, and a Hail Holy Queen, and the announcement of the "mystery" to be meditated upon during the next decade. Each day has its own theme for meditations to be contemplated (there are three traditional sets of mysteries: The Joyful, Sorrowful, and Glorious Mysteries, with Saint Pope John Paul II adding a fourth set, the Luminus Mysteries). The Rosary has a set of introductory prayers, and a closing prayer. A "Full" rosary, though not often completed by the lay, is a full set including all of the Mysteries, and one can purchase a "complete" Rosary consisting of 15 groups of 10 beads, versus the standard 5 found on most Rosaries.

According to a study published in the British Medical Journal (2001;323:1446-1449), researcher Dr. Luciano Bernardi, associate professor of internal medicine at the University of Pavia in Italy and his team tested whether rhythmic chanting, in this case reciting the rosary or using Yoga mantras, could have a favorable effect on the heart’s rhythms. What the team knew at the beginning of the study was that slow regular breathing was beneficial in preventing heart disease by synchronizing inherent cardiovascular rhythms.

Using 23 healthy adults whose heart rate and blood pressure were measured prior to the start of the study, the researchers measured their breathing rates while some participants prayed the rosary in the original Latin (Ave Maria), and others recited a given Yoga mantra. For comparison, the study participants’ breathing rates were measured during free talking and during slow breathing exercises also. What they noted is that the participants rate of breathing slowed down from fourteen breaths a minute (spontaneously) to 8 breaths per minute when they engaged in regular conversation, but breathing slowed down even more to six breaths per minute while reciting the rosary or the yoga mantra. Breathing at a slow six breaths per minute “has generally favorable effects on cardiovascular and respiratory function,’’ the researchers note. What’s more, the researchers found reciting the rosary or the yoga mantra both similarly synchronized all the hearts rhythms. 

It ends up that despite the cultural differences between the two spiritual practices, rosary chants and yoga mantras, Dr. Bernardi suggests that the two may have similar origins and both evolved as a simple way to slow respiration, improve concentration, and induce calm. The rosary while known to be related to the Catholic religion, was initially introduced by the Crusaders “who learnt a similar technique from the Arabs who in turn learned it from the Indian and Tibetan masters of yoga”, Dr. Bernardi states.